Surviving the Loss of Yao

Posted on February 27, 2008 by


On Tuesday morning the Houston Rockets received what seems like the worst possible news.  Yao Ming is not going to play anymore this season.  Since he’s clearly their most productive player, the Rockets (and Tracy McGrady) dream of playoff success are now over.

And then on Tuesday night we saw a different story.  The Rockets – without Yao – blew the Washington Wizards off the court. 

Such a result is reminiscent of last season.  On December 23rd of 2006, Yao fractured his leg.  This injury caused him to miss 32 games.  Across these 32 games, though, the Rockets managed to post a 0.625 percentage, a record that surpassed the team’s record with Yao in the line-up.

Can we expect to see such a story again this season?

The Rockets with Yao

Before we get to that question, let’s look at what the Rockets have done so far this season. Table One offers two projections of Houston’s Wins Produced.  The first assumes that what we saw from these players last season (except the rookies) will be seen this year.  The second projection assumes that what we have seen so far this season will be seen the rest of the 2007-08 campaign.

Table One: The Houston Rockets after 56 games

As one can see, both projections are quite similar. Had each player on the Rockets played as well as he did last season, the Rockets would be on pace to win 54 games. Given what these players have done this year, though, we would expect 51 victories.  The only real difference is seen with respect to the play of Bonzi Wells.  Last season Wells was uncharacteristically unproductive. This season, under Rick Adelman (the coach he played for in Sacramento), Wells has been well above average.

Of course, now he gets a chance to be well above average in New Orleans. So the departure of Wells doesn’t help.  His departure, though, also allowed the team to rid itself of Mike James.  James was playing very badly, so his loss is quite the positive.  In sum, the trade of Wells and James for Bobby Jackson doesn’t look like a transaction that is going to dramatically help or hurt this squad.

The loss of Yao, though, is another story.  Yao leads the Rockets in Wins Produced, more than doubling the production of the second most productive player (Shane Battier).  How can the team survive this loss?

Losing Yao

Last season Mount Mutombo came to the rescue.  For the 2006-07 season, Dikembe Mutombo posted a WP48 [Wins Produced per 48 minutes] that was more than three times the level posted by an average player. Such production – as I detailed last March – allowed the Rockets to survive the loss of Yao last year.

This year, though, Mutombo is offering quite a bit less. His WP48 of 0.068 is actually below average.  Now this could be for two reasons:

1. Mutombo is old.  He’s the last survivor of the 1991 draft class and he clearly is near the end of the line.

2. Mutombo hasn’t played much.  This is another possibility.  When a player doesn’t get consistent minutes his per-minute performance can drop.

In his first game back in the starting line-up, Mutombo offered 6 boards and 4 blocked shots in 23 minutes.  Such production was above average (on a per-minute) basis, suggesting that maybe reason #2 is plausible (of course he’s still old).  And if it’s reason #2, maybe we will see a repeat of what we saw last year.

But let’s ignore for a moment Tuesday night’s sample of one. Let’s say that Mutombo isn’t suffering from lack of playing time and that he really is old.  If this is the case, the Rockets might still be able to survive the loss of Yao.

To see this, let’s imagine the Rockets allocate minutes in the following fashion (inspired but what they did Tuesday night):

Rafer Alston: 32 [0.130 WP48]

Tracy McGrady: 36 minutes [0.103 WP48]

Shane Battier: 32 minutes [0.101 WP48]

Luis Scola: 34 minutes [0.085 WP48]

Dikembe Mutombo: 20 minutes [0.068 WP48]

Bobby Jackson: 16 minutes [0.094 WP48]

Luther Head: 26 minutes [0.065 WP48]

Chuck Hayes: 20 minutes [0.184 WP48]

Carl Landry: 20 minutes [0.298 WP48]

Given these minutes and these performance levels, the Rockets could expect to win about 49 games over an 82 game season.  In other words, they are not too far off the pace they were with Yao

How is this possible?  The key is the play of Carl Landry.  As I detailed a couple of days ago, Landry has been very productive for the Rockets this year.  With Yao out, Landry will get more minutes.  And if Landry maintains his production (a very big if given the size of the sample we have seen), the Rockets can still win without Yao.

A Few Caveats

Okay, a few other things to keep in mind.

1. I have only looked at nine players and there are certainly other players on the team. When Steve Novak, Gerald Green, and Aaron Brooks take the floor, the Rockets will be worse off.  So this level of wins I am projecting without Yao might exaggerate the team’s performance.

2. Then again, if Mutombo returns to what he did last year the 49 win projection is too low.  In other words, it’s possible for the Rockets can improve without Yao (which they did last year).

3. And this ignores the play of Luther Head.  Head was above average last year in more minutes.  Now that Wells is gone, Head might return to what he was in 2006-07.

Post-Season Success?

And now for the big story. Tracy McGrady has had a very good career.  Before injuries began to diminish his production, T-Mac was every bit as good (and I have argued more productive) as Kobe Bryant.  Despite this production, McGrady has never seen the second round of the NBA playoffs.  Can this change this year?

The Rockets are currently in the midst of a 13 game winning streak.  But when we look at the entire season we see a team with an efficiency differential (offensive efficiency minus defensive efficiency) of only 4.0.  This mark is currently bested by six other teams in the Western Conference.  In other words, the Rockets – given what they did across the entire season – are not likely to be favored in their first round match-up.

Although it’s possible that Houston can remain competitive without Yao, it doesn’t seem likely this team is going to be able to defeat one of the top seeds in the Western Conference in the first round.  This was true before Yao was hurt.  And it’s still true today.

So what does Yao’s injury mean for Houston?  It’s possible that they won’t lose with any greater frequency.  But now McGrady can offer a reason why (that doesn’t focus on McGrady) his team can’t get out of the first round again.  In other words, Yao’s injury gives this team a ready-made excuse.  And who said all injuries had to hurt?

– DJ

Our research on the NBA was summarized HERE.

The Technical Notes at provides substantially more information on the published research behind Wins Produced and Win Score

Wins Produced, Win Score, and PAWSmin are also discussed in the following posts:

Simple Models of Player Performance

Wins Produced vs. Win Score

What Wins Produced Says and What It Does Not Say

Introducing PAWSmin — and a Defense of Box Score Statistics

Finally, A Guide to Evaluating Models contains useful hints on how to interpret and evaluate statistical models.