Injuries and Zobrist’s Power Stroke

Ben Zobrist did everything for the Tampa Bay Rays in 2009. He posted 8.4 WAR and earned MVP consideration from out of nowhere despite entering the season with only 530 below-replacement plate appearances to his credit. With that given, perhaps it’s not surprising that the MVP candidate in 2009 was merely a solid contributor in 2010, posting 3.1 WAR in 151 games for the AL East Champion Rays. Zobrist was still a solid fielder all around the diamond in his second campaign as a full-time player. The difference instead was a stark drop-off in the power that fueled his .408 wOBA. In 2010, Zobrist’s ISO fell from .246 all the way down to .115, and with it his wOBA plummeted to .323. Which Zobrist will show up in 2011?

The opening weekend was a good sign for the Rays, as Zobrist clubbed a homer and a double (along with two other hard-hit outs) for an otherwise anemic Rays offense. A continued and extended quick start to the 2011 season would lend some credence to the possibility that a back injury suffered in July (and may have limited him earlier in the season as well) was a factor in Zobrist’s power outage from 2010. Zobrist’s power trends from last season seem to support this notion as well:

However, as we can also see in this trend, Zobrist was never really at his 2009 level during the 2010 season. His top ISO in any one month prior to the injury was .162 in May; he topped that mark in September with .175. These two marks were just under what we’d expect with regression – remember that power barely stabilizes over the course of a full season. ZiPS projected Zobrist for a .182 ISO, just over what he did with the two months sandwiching his injury.

This year, ISO projections for Zobrist have dropped down to the .160-.170 range. If Zobrist performs in that range, his wOBA should head back to .360, which could make him an all-star caliber performer once again. However, these projections don’t understand the injury which limited Zobrist through July and August. Even though we shouldn’t bet on a return to top-10 hitting numbers like 2009, Zobrist could become an elite player once again with a fully healthy season.