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2018’s Most Improved Ranger -- Shin Soo Choo

The aging on base machine appears to have another valuable season with the bat left in him.

MLB: Spring Training-Chicago Cubs at Texas Rangers Mark J. Rebilas-USA TODAY Sports

Opening day is finally here and the Texas Rangers have a peculiar situation on their hands. The Rangers chances of making the playoffs are generally assumed to be low and the statistical projections seem to support that thought. The long story short? The Rangers need to find value where there wasn’t much last year in many different places. The obvious answer for significant added value is from the young position players taking leaps forward, but what if I told you the most sizable improvement in outcomes could come from a player well over 30? Even more, what if that player didn’t even need to improve to do so? My pick to be one of the most improved performers in the lineup is none other than Shin-Soo Choo.

At first glance there doesn’t seem to be a lot of hope for the aging player on an “albatross” contact. Choo is going into his age 36 season after a 2017 season where he was worth about 1 win. His 107 wRC+ was solid, but more production is necessary to provide value as a defensive black hole/DH.

Normally with aging and declining outcomes you expect to find declining peripherals, but that’s just not the case for Choo. In 2017 posted a K rate below his career average, a walk rate above his career average, an isolated slugging just under his career average, and tied his career best 22 home runs. None of these suggest a hitter on the sharp decline that age inevitably brings.

Digging deeper, Choo’s batted ball performance tells a vastly different story than his outcomes would suggest. Choo posted a career high line drive rate at 25% and increased his HR/FB rate to his career high of 20.4%. Per Fangraphs, Choo’s Soft%, Med%, and Hard%, are right round or better than they were in his peak seasons. In addition, he seemingly has eliminated the weakness against left handed pitchers that plagued him earlier in his career, posting a 109 wRC+ against them in 2017.

Expected weighted on base average (xwOBA), an estimate of a player’s offensive value added based on exit velocities, launch angles, K rates, and walk rates, paints a very different picture than wRC+ does. Choo’s batted ball data and overall profile suggested that his weighted on base average (wOBA) should have been around .365; a full 21 points higher than it actually was. His xWOBA ranked 43rd in the MLB, just behind players like Kris Bryant and Logan Morrison and just ahead of players like Nolan Arenado and Cody Bellinger. xwOBA has a very strong correlation co-efficient with wOBA so it’s not too hard to see a bounce back just based on that.

Choo’s 2017 season also lines up similarly to his 2015, where he produced a 128 wRC+ and was worth about three and a half wins. The biggest differences appear to be that Choo made solid contact more often in 2017, but his launch angles were more conducive to success in 2015, which led to a miniscule 5 point gap xwOBA. The charts below from 2015 and 2017 tell a story of a player that is using the whole field more as he ages while maintaining his exit velocities, not of a player crashing into age related decline.

2017 Spray Chart
Baseball Savant
2015 Spray Chart
Baseball Savant
2017 Average Exit Velocity
Baseball Savant
2015 Average Exit Velocity
Baseball Savant

At this point it seems fairly reasonable to suggest that Choo’s 2017 was much more likely a statistical anomaly than a sign of a player in decline. If Choo just had a number of plate appearances that approached infinity, then the data suggests he would have ultimately been a valuable offensive asset (assuming the aging Choo could handle the longer season).

Unfortunately for Choo, what he did last year at 35 doesn’t necessarily mean he will do the same at 36. Age will eventually become a bigger factor for Choo and his batted ball data will dip along with his outcomes. It just hasn’t happened yet and there’s reason to expect that Choo could provide significant value for the Rangers in 2018.