Counting the Baskets

Tyler Zeller: Interim Rim Protector?

In the Celtics something outta nothing trade yesterday Danny Ainge picked up two assets, Tyler Zeller and a draft pick, and an over payed player, Marcus Thornton, on an expiring contract.   The top ten protected draft pick from Cleveland is the major prize.  But the Celtics front office is said to also like Zeller, who as a Center still on his rookie contract fills a need on the roster and comes with a relatively cheap contract.

So what kind of a center is Zeller?  

In overall metric terms the word that comes to mind is 'decent.' My draft class projection using the boxscore metric AWS, Zeller projected as the 21st in class based on his age and performance to date, approximately where he was drafted. His Win Shares per 48 minutes  were slightly above average and his RAPM (a stabilized version of adjusted plus/minus) puts him somewhat below average, with his defense rating above average and being offset by a below average 

On offense Zeller was much more efficient last year than in his rookie year, with his True Shooting percentage (TS%) jumping from .486% to .581%, a tremendous jump.  That was mainly achieved by improving his shot selection, or at least shortening his range with his average shot distance from the basket dropping from 9.9 to 6.3 feet. In fact, over 50% of his attempts came within 3 feet of the basket, and the mid-range shots dropped, according to Basketball Reference as shown below.

 

																					2-Pt Field Goals			3-Pt Field Goals
									% of FGA by Distance						FG% by Distance							Dunks			Corner		Heaves
Season	Age	Tm	Lg	Pos	G	MP	FG%	Dist.	2P	0-3	3-10	10-16	16 <3	3P	2P	0-3	3-10	10-16	16 <3	3P	%Ast'd	%FGA	Md.	%Ast'd	%3PA	3P%	Att.	Md.
2012-13	23	CLE	NBA	C	77	2033	.438	9.9	.993	.335	.195	.118	.345	.007	.441	.594	.385	.348	.358	.000	.800	.066	31		.000		0	0
2013-14	24	CLE	NBA	C	70	1049	.538	6.3	.997	.510	.238	.100	.148	.003	.540	.649	.362	.517	.465	.000	.795	.107	30		.000		1	0
Career			NBA		147	3082	.472	8.7	.994	.395	.210	.112	.278	.006	.475	.618	.376	.400	.377	.000	.798	.080	61		.000		1	0

Provided by Basketball-Reference.com: View Original Table
Generated 7/9/2014.

He also improved his shooting percentages on the few mid-range shots he did take. So, if that continues, spacing won't be too much of an issue.

In addition, Zeller dramatically increased his free throw rate, a measure of how many trips to the line a player gets per shot from the floor, from .287 free throws per shot to .417.  

On the down side, his distribution numbers took a big hit from a low base last year with a assist to turnover ratio of .57, well below average.

One of the main issues with last year's Celtics was rim protection, with only Vitor Faverani, who struggled with consistency issues before being injured, as a true Center on the roster.  Zeller is no Omer Asik or Larry Sanders, or even Epke Udoh, for that matter, but his rim protection numbers are a step above the power forwards Boston played out of position last year as centers.  Zeller averaged 1.7 blocks per 48 minutes, putting him in the middle of the pack of Boston's bigs last year (ahead of Bass, Sullinger and Olynyk, behind Faverani and Humphries).  

Using advanced rim protection data Zeller scores a little better.  Using SportVu data Seth Partnow developed a Rim Protection Points Saved (RPPS) metric that measures both how often a player contests shot near the rim and what their opponent's field goal percentage was when they do.  Like all of the SportVu data it won't be until the end of this year when we can start to really determine how consistent player performance is, but the RPPS metric might give us a more complete measure of rim protection than simple blocks.  

In RPPS Zeller ranked 32nd in points saved at the rim per 36 minutes with 8.43 contests at the rim per 36 minutes with opponents shooting 47% on Zeller contests (league average being 50%) in data through 3/22/2014.  As this table via Partnow's data shows, Zeller may be an improvement over every player from last year except for Faverani, who fouled too often and over helped too often for his contests at the basket to help the defense.

 

Player	Opp FGP at Rim	Contests/36	AdjSaved	AdjSaved/Gm	AdjSaved/36	Adj/36 rank
Vitor Faverani (BOS)	46.10%	11.34	83.9	2.27	6.14	20
Tyler Zeller (CLE)	47.40%	8.43	127.3	2.19	5.45	32
Kris Humphries (BOS)	50.30%	10.42	177.8	2.87	5.06	42
Jared Sullinger (BOS)	53.10%	9.08	196.5	3.02	3.97	81
Kelly Olynyk (BOS)	54.60%	7.97	96.5	1.66	3.09	117
Brandon Bass (BOS)	53.20%	5.48	118.4	1.69	2.21	155

 

This makes me think that Bass-Olynyk line ups should never ever, ever, ever, happen.

Ok, summing up, briefly, again Zeller is a decent young-ish player that fits a roster need on a cheap contract.  He brings some things the Celtic's need like being a relatively legitimate Center and playing defense like one, meanwhile his overall efficiency might not be as beneficial on offense as it first appears due to his lack of distribution numbers and (possible) spacing issues. He is still relatively young and playing on a cheap rookie contract.  Not bad for cap space the Celtics didn't have.

Valuing Avery Bradley

My working theory on Danny Ainge right now is that he over values 'his guys,' and has what behaviorial economists sometimes call this 'pride of ownership' or ownership bias. A tendency where we over value something either because it is 'ours' or because we feel we had a part in developing it.

That explains on the one hand why Ainge is a good trader.  Even though he is always looking for a deal, he rarely takes something unless he gets a quality return.  It also explains why he tends to give what are arguably above market deals for guys like Jeff Green and Avery Bradley.

In short I am not a big fan of the deal the Celtics struck with Bradley, though I don't think by any measure it's a team killer or poison contract.  It is just placing a bit too much value on Bradley as he stands now.

As I see it the plus/minus leadger on Bradley looks something like this, pluses first:

• Defense: Bradley gives tenacious on ball defense.  Though he is not elite in steals.  He is rated as the 9th most impactful guard on the defensive end in Jerry Englemann's RAPM.
• Outisde shooting: Bradley shot 39.5% from three last year, 36.6% career.
• Age: Bradley is only 23, about the same age as Kelly Olynyk, Adreian Payne or Doug McDermott.

The Minuses:

• Ball handling:  AB isn't a point guard, as I noted last year coming into the season. He isn't really even a combo guard.
• Shot selection: Bradley's shot selection is something of an analytic nightmare.  Last year he took way too many shots with his heal on the three point line instead of his toe just behind it.
•  Reversion of shooting: Bradley shot 39.5% last year, from 3 but only 31.7%the year before. This is the one that worries me least.  There's a general, though not immutable, upward trend to shooting from distance for NBA players.  Some of that is survivorship bias, but shooting is a learnable and trainable skill with improved muscle memory. In any case, something just above his career 36.6% would be a productive number.
• Injuries:  Bradley has missed a significant portion of three out of his four seasons with different injuries.  I think this one is a bit overplayed, but I don't dismiss it out of hand.  The ankle injuries being the primary concern here since there have been some recurrance of the same injury.

Looking at overall numbers, there is no easy way measure the 8 million a year based on Bradley's current production.  For example Daniel Myers' ASPM estimates  Bradley's production last year would have been worth $3 million in terms of value over replacement.  Though these estimates can vary, for example, RAPM, which rates Bradley much higher based on his defense would give him an estimate somewhere closer to his actual $8 million contract.   Given that RAPM is generally more favorable to Bradley than any other metric, it looks like the $8 million figure is near the top of the acceptable pay scale for Bradley's current production (though with the salary cap rising this will adjust upwards).

Of course, one should pay for future production, not past (special attention to Mitch Kupchack). The easiest way for Bradley to increase his value added would be to play closer to 82 games. Beyond that, looking at the negatives list, the easiest to address should be shot selection.

Bradley is an inefficient scorer right now not because he is a bad shooter, but because he shoots from bad places.  Boxscore Geeks shows him to be below average for a shooting guard in terms of eFG% and TS% last year and for his career.  But his shooting zone chart looks much better than that would suggest.

He actually excelled on Above the Break threes and held his own inside and from the corners.

But when one looks at where those shots came from, a sight burned into my corneas after 82 games last year, the chart is less pretty.

 

Below is Bradley's shot zone percentages both in terms of selection and field goal percentage, via Basketball Reference:

 

																					2-Pt Field Goals			3-Pt Field Goals
									% of FGA by Distance						FG% by Distance							Dunks			Corner		Heaves
Season	Age	Tm	Lg	Pos	G	MP	FG%	Dist.	2P	0-3	3-10	10-16	16 <3	3P	2P	0-3	3-10	10-16	16 <3	3P	%Ast'd	%FGA	Md.	%Ast'd	%3PA	3P%	Att.	Md.
2010-11	20	BOS	NBA	PG	31	162	.343	13.1	.925	.313	.060	.075	.478	.075	.371	.667	.250	.200	.219	.000	.391	.060	4		.200	.000	0	0
2011-12	21	BOS	NBA	PG	64	1368	.498	11.1	.866	.410	.087	.057	.311	.134	.511	.661	.200	.522	.400	.407	.629	.045	14	1.000	.648	.571	0	0
2012-13	22	BOS	NBA	PG	50	1435	.402	13.9	.736	.295	.069	.067	.305	.264	.432	.482	.273	.313	.445	.317	.487	.019	8	.950	.825	.337	0	0
2013-14	23	BOS	NBA	PG	60	1855	.438	15.8	.758	.187	.081	.064	.425	.242	.451	.597	.284	.321	.439	.395	.543	.027	17	.937	.625	.368	0	0
Career			NBA		205	4820	.438	14.1	.783	.271	.078	.064	.369	.217	.458	.588	.259	.354	.422	.366	.548	.030	43	.950	.688	.381	0	0

Provided by Basketball-Reference.com: View Original Table
Generated 7/4/2014.

As one can see, Bradley's long two spiked last year with > 16 foot twos hitting 42.5% of his shots.  Even being above average at this shot is not a recipe for efficient offense.  At the end of the season Bradley took, and made more above the break threes than he had at the beginning.  I felt like he had lacked confidence at the start in taking the above the break shot. But, if Bradley could roughly flip his long two selection and three selection, not necessarily an easy task, he could improve his true shooting percentages even if he reverts to his career efficiency numbers of 36.6% on threes.  

Another area of concern is the lack of shots around the rim.  Bradley's percent of shots taken there has fallen the last three years.  In the half court Bradley's lack of handles and court vision limits his attempts largely to shots off of cuts, so pairing him (maybe) with Rondo for a full season along with Marcus Smart should increase Bradley's opportunities somewhat. But, I have my doubts that he will be able to repeat the rate he acheived his second season before the scouting book on him was complete.

The easiest way to sum up is that Bradley's value has to be as a 3 and D guy with opportunitistic cuts to the basket.  Shots with his heal on the line don't count.