APBRmetrics

[Doc319]

Based on past discussions here (actually, in APBR Analysis), Antoine Walker fares pretty poorly in most people's rating systems. Today there is an article about how much of a positive impact Walker has had on the Celtics since his return to Boston. I am interested if Walker's performance this year--or at least in this 6 game stretch--measures up differently than it did in previous seasons. Has Walker's game changed in some measurable way? Or does analysis of his game somehow miss his contributions to team chemistry? Or is six games too small of a sample size?

Danny Ainge is supposedly guided in his decision making process by the "brain typing" theory, which raises the question of whether Walker's brain suddenly rewired itself to fit in with Ainge's plans after supposedly being so incompatible with the Celtics' new direction.


Here is the link to (and brief excerpt from) the article lauding Walker's contributions to the Celtics since his return.

http://146.145.120.3/default.asp?c=startribune&page=nba/news/ACN3791776.htm


Walker is just what the Celtics needed
By Warren Blatt, Sports Network NBA Editor

(Sports Network) - The Boston Celtics are a different team since re- acquiring forward Antoine Walker at the trade deadline.

...Since being brought back to Boston, which is 5-1 since the trade with Atlanta, Walker has averaged 20.3 points and 9.2 rebounds in just under 35 minutes of action per game. The Celtics look like a more complete team, as the offense is more potent and the team chemistry is evident.

--David Friedman
Contributing Editor, Basketball Spotlight
http://www.suite101.com/welcome.cfm/basketball_spotlight

[jkubatko]

[Mike G]

Sometimes I think I'm the only statistics person who doesn't hate Walker. He's a bit off his career rates this year, but not much. What people seem to hate most is his TS%, a career .479, which is right about where he is this year.

So I have him ranked as the #73 most effective player this year (at 27.3; Duncan is #1, at 46.

In eWins, thanks to his 40 MPG, he's at #44, with 5.3 -- between Bosh and Gasol (who has missed 20 games). Garnett is #1, with 11.8

I'm not declaring Walker to be any kind of superplayer. His slippage in concentration might be seen in his FT%: from .74 just 3 years ago, to .55 this year. Almost nobody becomes a bad FT shooter at this stage in their careers.

[Ben F.]

I think what most people in the statistical community dislike about Walker is the abhorrent +/-. I know before leaving Atlanta he was worst in the league among players playing significant minutes with a -17.7 "Roland Rating". That's such a huge number it's hard to ignore. You'd think he was doing something to hurt the team. Then looking at the On/Off Court splits, the team played 5% worse eFG% defense with him on the court than off.

Yet since the trade those numbers have shrunk. It seems the Hawks are playing worse without him. The Roland Rating is now at -11.8 and the dFG% difference is at 3.6%.

This is incredibly confusing to me. The numbers before would seem to suggest that not playing Walker would be a lot better for the Hawks, but they've played significantly worse without him.

To the Celtics' side, I think 6 games is a tad small. In their first game, they won, but Walker was a -6 in that game, while helping the Celtics' opponents to shoot 8% better that game with him on the floor than off. Since then he's been great it seems. His Roland Rating is up in the positives, for the first time since he was on Boston last time, I think. +0.8 is an achievement for him.

But he still confuses me. He's inefficient, turns the ball over, is an average rebounder for a PF, and is a horrible defender. Yet for some reason he seems to contribute to Boston.

[Ben]

[bchaikin]

Based on past discussions here (actually, in APBR Analysis), Antoine Walker fares pretty poorly in most people's rating systems.

Sometimes I think I'm the only statistics person who doesn't hate Walker. He's a bit off his career rates this year, but not much. What people seem to hate most is his TS%, a career .479, which is right about where he is this year.

I think what most people in the statistical community dislike about Walker is the abhorrent +/-. I know before leaving Atlanta he was worst in the league among players playing significant minutes with a -17.7 "Roland Rating". That's such a huge number it's hard to ignore. You'd think he was doing something to hurt the team.

I don't think he's that bad. He's got an above average PER this year too.

rather than doing some sophisticated statistical analysis, let's just use some common sense to show that antoine walker is indeed one of the worst starting PFs in the league, and has been for quite some time. simulation shows this, but let's look at some simple logic and then some simple raw numbers...

games are won and lost in the nba based on points scored, nothing else. the average team possession today results in a team scoring 1.04 points. lets round that off for the sake of argument and say one point. so what's the worst thing a team can do on a single team possession? not score of course....

the worst overall thing an individual player can do for his team on any single team possession is to be personally responsible for his team not scoring. the two most common ways for this to occur are (1) for the player to commit a turnover and his team lose possession of the ball to the opponent (with his team not scoring at all on that team possession), and (2) for the player to miss a shot (2pter or 3pter) and the opponent get the defensive rebound (with his team not scoring at all on that team possession), or to miss a FT that is then rebounded by the defense (yes i know the first FT could be made)...

lets use some simple math and see which players do the above the most. right now 0.714 of all rebounds are defensive, and 0.85 of all missed FTs that are available to be rebounded are defensive (those numbers may be off some but i'm guessing not by much). lets also assume that half of all of a player's missed FTs are rebounded (i.e. the 1st of 2 FTs that are missed are team rebounds). so a simple crude formula/estimation to show which players account for the most team possessions that result in zero points scored is:

( (FGA-FGM) x 0.714 + (FTA-FTM)/2 x 0.85 +TO )

doing this on a per game or per minute basis here are the nba's leaders for team possessions resulting in zero points scored:

per game:

15.1 allen iverson
13.8 kobe bryant
12.4 antoine walker
11.9 tracy mcgrady
11.7 jermaine o'neal

per minute:

0.373 allen iverson
0.358 jermaine o'neal
0.350 kobe bryant
0.346 shaquille o'neal
0.338 antoine walker

here are the above player's Scoring FG%s:

.558 shaquille o'neal
.537 kobe bryant
.519 tracy mcgrady
.513 allen iverson
.511 jermaine o'neal
.471 antoine walker

now, if a single player is going to be personally responsible for his team getting alot of team possessions that result in no points being scored, then he better be doing other things on the court to make up for that, otherwise he has no business being on the court as he will not generate many wins for his team. one way would be to get alot of steals, so that the opponent has a number of team possessions that also result in zero points scored. another way would be to play very good defense so that the man he guards misses alot of shots as something like 0.714 of those misses will be rebounded by his team (and be an opponent team possession with zero points scored). another way would be to block alot of shots as somewhere around 60%-65% of all blocked shots are rebounded by the defense...

but if you're not getting alot of steals (or forcing alot of turnovers, which unfortunately we don't have stats for - yet), or are not forcing alot of misses by your opponent, or are not blocking alot of shots, you're not causing your opponent to have alot of team possessions with zero points scored...

antoine walker does not get alot of steals, he doesn't block alot of shots, and almost all the data i have seen suggests he is not by any stretch of the imagination a good defensive player. so he personally is certainly not responsible for forcing the opponent into alot of team possessions resulting in zero points...

let's compare two players - antoine walker and shawn marion. i pick shawn marion as he is also a power forward, plays as many minutes as walker does, scores about as any points as walker does (marion 19.2 pts/g, walker 20., and as we all know is playing great this season. but the key difference is that while walker is personally responsible for about 12.4 team possessions per game with zero points being scored, marion is responsible for just 7.8, 37% less. on a per minute basis walker accounts for 0.338 team possessions with zero points scored, marion just 0.204, almost a 40% difference...

they have both played around 2300/2400 minutes so far, but while marion has 128 steals and 92 turnovers (a difference of +36 team possessions with zero points scored), walker has 69 steals and 199 turnovers (a difference of -130 team possessions with zero points scored). that's a total difference of 166 team possessions with zero points scored between the two players, or about 2 per game. this shows how much better marion is than walker - even if all of their other stats were identical, which they are not...

marion has 5 more FTM, but 100 less FTA than walker (as of last week). marion has 100 more rebounds (slightly inflated by the suns faster game pace), and twice as many blocked shots (86 to 44)....

is the above calculation for determing team possessions resulting in zero points exact? of course not, its simply a course estimation. yet walker has a Scoring FG% five percentage points below the league average (.471 versus .519), he turns the ball over on 7% of his touches, one of the highest marks for a player getting as many touches/min (1.2) as he does, and is not a good defender...

knowing all this is it any wonder that simulation shows the suns win 13 more games per average 82 game season with marion playing 40 min/g at PF than with walker? typically the best player at a specific position will win 15-16 more games per 82 games than the worst starting players in the league at that same position (duncan and kirilenko are even better than marion this season, by 2-3 more wins), which means walker is near the very bottom in terms of generating wins for his team as a starter at his PF position...

[Doc319]

Bob, your analysis is thorough and logical--yet the Celtics have done well since acquiring Walker. So, the question is, is this simply the result of a small sample size? If Walker is in fact so demonstrably bad (and I am not disputing your analysis of the numbers), what reason did the Celtics have to believe that he could help their team? (I realize that none of us can know the answer to this for sure--it could be a salary cap move, something to appease fans in Boston who like Walker, etc.) I assume, based on the results of your simulation, that you would predict that the Celtics will not continue to do well. I guess if the Celts continue to play well, we can look at Walker's stats again and see if he is turning over a new leaf this year or if he is contributing something that is hard to quantify.

I found it interesting that FFSBasketball's reply listed things that Walker does poorly and yet noted that the Hawks are worse since he left and the Celtics are better. This is what I find so interesting about Walker--he seems to be a difficult player to make sense of statistically.

[kjb]

I've long been befuddled by Walker's play. He sometimes make passes or plays that demonstrate to me that he sees the floor well, that he understands the game, and that he's a very smart player. Then two trips later he jacks up a 30-footer with a hand in his face and 22 seconds left on the shot clock. A few years ago, I honestly thought that he had the ability to be among the league leaders in assists and efficiency, if he'd just cut out a few of the silly shots and play with the smarts I thought he had. But that's not the way he's wanted to play. Puzzling.

One thing to look at for why Boston might be doing better in the 6 games since acquiring Walker is the fact that Walker is playing better.

[Mike G]

Walker obviously doesn't get minutes due to his scoring efficiency. Suddenly, he's become a shotblocker, but that will surely ease up shortly.

But 9 rebounds a game = 9 possessions. Good defense has 2 main components: (1): forcing bad shots, and (2): limiting the opponent to 1 shot; i.e., defensive rebounding. (I know, limiting to 0 shots is better..)

The guard's defensive job is to hound the ballhandler and get in the face of the shooter. The inside player's job is to limit access to the basket, box out, and secure rebounds.

For a team as bad as the Hawks, Walker's 40 minutes didn't seem out of scale with his contributions. If +/- numbers show the team was appreciably better without him, I have to ask if those other 8 minutes were mostly garbage minutes.

Meanwhile, he may be a case study for the benefit of limiting minutes. Maybe he's no longer capable of 40 Quality minutes. I've always thought a player should know how many minutes he's expected to play; and he should go 100% while he's in the game. On a team as thin as Atlanta, Walker's 80%-effort times still may have been more effective than some guy named Josh.

[S.K.]

One of the things about PER that I've noticed is that simply using a ton of possessions without screwing up ALL of them will give you a decent PER even if your numbers are otherwise poor. Look at Walker - his TO rate this year is poor, his rebounding is consistently below-average for a PF, and he puts up a low PSA/TS% year after year. Even his assist rate plummeted this year. Yet, a 25.2% Usage rate, and a 15.65 PER. Huh?
_________________
No books - no articles - no website.
Just opinions.

Ill-informed opinions.

[Doc319]

Boston won again tonight, beating Washington 105-101 with Walker scoring 11 points and leading the Celtics with 12 rebounds. More interesting than that, though, is this excerpt from Lacy Banks' column in today's Chicago Sun Times:


[quote]Walker has solidified the Celtics and has them contending for the Atlantic Division title. Beyond the expected scoring boost, Walker has provided Celtics coach Doc Rivers with some tough defense. The Celtics were 5-1 in their first six games with Walker back.

"Really, he's been phenomenal,'' Rivers said. "He's putting pressure, he's denying, he's fronting, he's taking guys off the post. Shoot, he's probably been our best post defender right now, and it's nice.''[/quote]



From what I read here, the stats and simulations show Walker to be a poor defender, yet Doc Rivers singles out his defense for praise. Unless Rivers is using some kind of reverse psychology (praise Walker for defense to inspire him to play good defense), he must be seeing a different game than the numbers are showing (or, again, perhaps this is the result of a small sample size). I watched the game tonight on NBA TV (which used the Boston feed with Gorman and Heinsohn broadcasting the game) and a stat was shown that Boston is averaging about 5 ppg more as a team since reacquiring Walker. Again, we all know the sample size is small and the strength of opposition during this run may not be top notch, but I just find Walker to be a fascinating case for two reasons: (1) he and Ainge exchanged such bitter words and now it is all seemingly forgotten; (2) Walker seems to be "enemy #1" (not as a person, but for his style of play and lack of efficiency) of many numbers crunchers, yet--at least in the short term--he and Boston seem to be confounding his naysayers.


--David Friedman
Contributing Editor, Basketball Spotlight
www.suite101.com/welcome.cfm/basketball_spotlight

[kjb]

[SGreenwell]

Reviving this dead thread out of curiosity, and because I'm a Celtics fan...

I've seen how Walker's numbers have improved since the trade, but how bad was Mark Blount before the trade? Al Jefferson? Raef LaFrentz? Those are the minutes Walker is getting, and Blount in particular has drawn the scorn of the Sports Guy and others.

Also, there has been mention of a "ripple effect" by people in regards to Walker. As long as he's not jacking up a 3, you do have to guard him, and he can pass. Is this freeing up Pierce, Payton, Delonte West and others for better opportunities? Have their scoring percentages increased?

[mavs128]

I remember being impressed with his man-to-man defense at times last year in dallas.....he's not a help defender, but I remember particularly well a gutsy effort he put in against Shaq.


On the other hand, I also know he was getting alot fewer minutes down the stretch, and the mavs seemed to be playing better.

[bchaikin]

antoine walker is doing very little different in BOS than in ATL. his touches/min in ATL were at 1.2, in BOS in 12 games at 1.1, his reb/48min in BOS in 12 games is at 11.8, in ATL 11.2. he is shooting the ball per touch (39%) and turning the ball over per touch (7%) just the same, he is getting fouled slightly less per touch in BOS (9%) than in ATl (11%).. he is also committing fouls at the same rate of 7 per 100 minutes played...

what he is doing is shooting a Scoring FG% of .532 in BOS, versus .466 in ATL, and is blocking shots two and a half times better in BOS than in ATL. as a matter of fact he's blocking shots in 12 games in BOS at a rate almost twice as good as his best annual rate (he's blocking in BOS 2.3% of all opponent FGA versus 0.9% in ATL, and his best previously in a season was 1.4%)...

sounds to me like he's playing for a contract, just like rasheed wallace did in DET last season in 22 games. last year in DET wallace grabbed rebounds at his career best rate per 48 min (11.1) and blocked shots much better than he ever had (4.1% of all opponent FGA in 22 games versus a previous career best of 2.8% in any one season). to his credit this season he is still rebounding that well, but his shot blocking has gone back to pre-DET days...

can't wait to see BOS sign walker to a huge new contract only to be regretting it in less than a year's time. by this time next season they'll be saying he's reverted back to the "old" walker when all along some statistical analysis would have shown them any good he's doing now is merely a blip on his career screen...