NBA Position Battles: Should Marcin Gortat Continue to Start at Center for the Wizards?

The Wizards' numbers with Gortat at the five have been horrible since the All-Star break. Is it time for a switch?

The Washington Wizards have had one of the most stable starting lineups in the NBA this season, with the combination of John Wall, Bradley Beal, Otto Porter, Markieff Morris, and Marcin Gortat starting 66 of a possible 74 games.

The Wiz currently sit in third place in the Eastern Conference with a 46-29 record, so it's not like they're in dire need of a shakeup, but it's hard not to notice how poorly they've been playing when Gortat has been on the floor since the All-Star break.

In Gortat's 485 minutes of floor time over that 20-game span, the Wizards have had a net rating (points scored minus points allowed per 100 possessions) of -7.4, as compared to the 5.7 mark they've had in his 485 minutes on the bench. Those are easily the lowest on-court and highest off-court net ratings on the team over that period, and thus Gortat has also had the worst on/off-court differential.

He might be an entrenched starter, but the fact that the Wizards have been 13.1 points per 100 possessions more efficient overall with Gortat off the floor lately suggests a change might be in order.

Let's see what the numbers say about backup center Ian Mahinmi, and how he would serve as a Gortat replacement.

When looking at the per-36-minute numbers between the two centers since the All-Star break, Mahinmi holds his own with Gortat.

Player PTS/36 FG% FT% REB/36 AST/36 STL/36 BLK/36 TO/36
Gortat 11.6 47.9% 56.4% 12.9 1.5 0.4 0.4 2.2
Mahinmi 12.3 58.2% 61.1% 10.2 1.2 2.3 1.5 2.3

In terms of points, rebounds, assists, and turnovers, the two have practically identical lines, while Mahinmi has a clear advantage in shooting efficiency and defensive stats.

If you look at their advanced stats on the season as a whole, the similarities persist.

Category Marcin Gortat Ian Mahinmi
nERD 2.3 0.4
Offensive rating 115 110
Defensive rating 107 103
Player efficiency rating 15.1 14.5
Win shares 6.2 1.1
Win shares per 48 minutes .126 .129
Box plus/minus 0.0 0.5
Value over replacement player 1.2 0.3

Gortat has an advantage in cumulative stats, like win shares and value over replacement player, by virtue of the fact that he's played 75 games and 2,382 minutes to Mahinmi's 25 and 435 this season -- Mahinmi missed 50 of the team's first 51 games due to knee issues.

Beyond that, however, the two are fairly similar in player efficiency rating, win shares per 48 minutes and box plus/minus, with Mahinmi even getting the advantage in the latter two categories.

So, if the two players have similar averages and grade out practically the same in most individual advanced metrics, why bother making the switch?

Well, for starters, if you look at each player's impact on rim protection, according to's defensive impact statistics, Gortat is miles behind Mahinmi when it comes to holding opponents to a low field goal percentage within five feet of the tin.

Marcin Gortat 4.7 8.1 58.0%
Ian Mahinmi 2.1 4.6 44.8%

A 13.2% difference in defensive field goal percentage at the rim is simply monstrous, especially when Washington's power forward, Markieff Morris, allows opponents to shoot a mediocre 51.2% at the rim himself.

And that's not where the defensive advantages of Mahinmi over Gortat end. If you look at each player's on/off-court splits since the All-Star break, the difference in defensive efficiency is huge.

Situation MIN Off Rtg Def Rtg Net Rtg REB% eFG%
Gortat On 485 109.5 116.8 -7.4 48.9% 51.9%
Gortat Off 485 109.0 104.2 5.7 49.4% 52.5%
Mahinmi On 367 107.7 102.2 5.5 50.3% 52.4%
Mahinmi Off 603 110.9 115.4 -4.5 48.5% 52.0%

The Wizards might be slightly better on offense with Gortat on the floor instead of Mahinmi, but the difference in defensive rating is borderline ridiculous and practically impossible to ignore.

The Wizards allow 12.6 more points per 100 possessions when Gortat is on the floor, as compared to when he's on the bench. Conversely, they allow 13.2 fewer points per 100 possessions when Mahinmi is on the floor than when he's off. Gortat might be a better offensive player than Mahinmi, but Washington has plenty of offensive fire power in their starting five between Wall, Beal, Porter, and Morris. They could use Mahinmi's defensive presence.

There's some proof of that in the five-man lineup data since the break. The sample size of the regular starters with Gortat is large enough at 331 minutes, but the version with Mahinmi in his place is a little small with only 28. Even so, the numbers are jarring.

5-Man Lineup MIN Off Rtg Def Rtg Net Rtg
Including Gortat 331 108.3 112.9 -4.6
Including Mahinmi 28 126.4 94.1 32.4

Small sample size or not, the Gortat lineup is not cutting the mustard, particularly on defense. The Mahinmi sample doesn't have enough minutes yet in order to make any definitive conclusions, but there's certainly enough there to suggest it's at least worth a shot over Washington's regular starting five.

Wizards head coach Scott Brooks doesn't exactly have a history of being flexible with his starting lineups (he brought James Harden off the bench past the point he probably should have and started Kendrick Perkins 292 games between the regular season and playoffs over five seasons in Oklahoma City), but this might need to be the time to change that.

The Wizards were hot going into the All-Star break, but have slipped a bit since, registering a pedestrian -0.8 net rating in their last 20 games (17th in the NBA over that span), despite a decent 12-8 record. If they want to turn things around and go into the playoffs on a high note, they may want to bite the bullet and swap in Mahinmi for Gortat while there's still time to make the necessary adjustments.