Substituting DRS for UZR in WAR by Joe Pawlikowski November 23, 2010 When we calculate WAR at FanGraphs, we use a player’s UZR as his defensive input. This holds true for all positions except catcher, which defer to defensive runs saved (DRS), since UZR does not measure defense for catchers. That led me to wonder what would happen if we used DRS across the board. How big a difference might we see in the WAR values of the league’s best players? For the players at the very top of the WAR leader board there wasn’t a huge difference. Josh Hamilton, for instance, loses just 0.9 RAR when we substitute DRS for UZR. That moves him very slightly, from 8 to 7.9 WAR, which would still lead the league. Joey Votto takes a similarly small hit, perhaps not even enough to move his WAR 0.1. Even Albert Pujols doesn’t take much of a hit. It’s after those three, though, that things start to get interesting. The first one to get a big bump is Ryan Zimmerman. UZR credited him with 13.9 runs above average, which ranked third among MLB shortstops. DRS, on the other hand, credits him with 20 runs above average, which increases his RAR to 75.2. That would put him second in the league in WAR — it would hold up because Hamilton, Votto, and Pujols take that small hit from the UZR to DRS switch. Still, DRS still doesn’t rate Zimmerman as the best third baseman in the league. That honor belongs to UZR leader Chase Headley. Robinson Cano, nominative MVP candidate, would also benefit if we substituted DRS for UZR in WAR. While he ranked below average with a -0.6 UZR, he ranked quite higher with DRS, seven runs above average. That would bump his WAR to around 7.2, which would move him all the way to fifth in the league. His passing of Adrian Beltre would stand, since Beltre takes a slight hit with DRS. He would not, of course, pass Zimmerman, since the alternate WAR has Zimmerman around 7.6 WAR. What of Jose Bautista? By outslugging the league by a significant margin he produced 55.9 park-adjusted batting runs above average, but defense took him down a peg. Between third base and the outfield he checked in at 7 runs below average per UZR. Yet DRS saw something different. If we change WAR to reflect Bautista’s 6 DRS we’d have him at somewhere around 8.1, 8.2 WAR. That would trump Hamilton, since as we saw above he takes a slight hit with DRS. Evan Longoria presents an interesting case. He led the league in bWAR, but finished just sixth in our WAR. Changing UZR to DRS would give him 1.9 additional runs above average, bumping him to around 7.1 WAR. That would put him right around Beltre’s level, if not a bit higher. If we’re looking for a player who scored lower on DRS than UZR, we can look to Longoria’s teammate Carl Crawford. By UZR he ranked the league’s second best left fielder at 18.5 runs above average. Change that to DRS, though, and he has only 14 runs above average. That downgrades him from 6.9 WAR to around 6.5 WAR. We can see the same in Andres Torres. His 6 WAR is based heavily on a 21.2 UZR. DRS sees things differently, crediting Torres with just 12 runs above average. The change amounts to a huge difference in WAR, knocking him all the way to 5.4. Instead of ending on the negative, let’s close this exercise with someone who gets a decent boost from DRS. That would be Troy Tulowitzki. While UZR credits him with 7.1 runs above average, an impressive figure considering he missed a decent chunk of time, DRS bumps that to 16 above average. That gives him nearly an entire win bump, from 6.4 to around 7.4. That would place him ahead of Albert Pujols. What we can do with these changes I’m not exactly sure. Both UZR and DRS use the same data from Baseball Info Solutions, but they interpret it differently. I’m sure we could conduct a similar experiment using Total Zone, or even Colin Wyers’s nFRAA, neither of which uses the BIS data. It’s just something to consider when using any version of WAR to rank players.