
About a week ago, using Josh Hermsmeyer’s injury database that lists player injuries from 2002 to 2008, Dan Turkenkopf of Beyond the Box Score examined the way in which wrist injuries might impact power (it seems common sensical to assume that they do, but I appreciate having some form of data to support this theory, even if it is limited). Basically, Turkenkopf looked at players with wrist injuries during the aforementioned timeframe and compared their projected ISOs – the projected ISOs were calculated by Turkenkopf using the Marcel projection system – upon returning from their wrist injuries, to their actual ISOs upon returning. In the end, though the analysis was only the “quick and dirty” starting point to what might one day be a larger, more comprehensive study, Turkenkopf concludes that “there may be something to the idea that wrist injuries take away a player’s power during his recovery,” as the “overall mean difference between the projected ISO and the actual was -0.030, which is pretty substantial.”
Nick Johnson, the Yankees designated hitter (and possible number two hitter), is actually one of the 77 players featured in Turkenkopf’s study, for he spent 27 days on the disabled list with a bruised wrist in 2002 – a relatively minor wrist injury – while also spending 137 days on the disabled list in 2008, missing the rest of the regular season after suffering a torn wrist tendon, which, unlike the bruised wrist, was obviously a much more significant injury. In accordance with injury severity, Johnson surpassed his ISO projection upon returning from the disabled list in 2002, however, last season, after returning from his ’08 tendon tear, Johnson saw a rather large divide between his projected ISO of .208 and his actual ISO of .114 (a difference of .094). As Turkenkopf noted, and via common sense logic, the wrist injury did seem to drain Johnson’s raw power in 2009 – explaining his David Wright-like home run total of eight – after he had posted a .190 ISO in 2005, .230 in 2006, and a .211 mark, prior to his injury, in 2008.
I think it is safe to say that, another year removed from his wrist injury – he will have received two years of recovery time, essentially – should allow Johnson to inch closer towards his career ISO of .174. This is another instance where a player did so poorly in one category that he is bound to improve given his overall track record in that area. Marcel, the system Turkenkopf used for his ISO study, forecasts Johnson’s ISO to be .137 in 2010. As a left-handed hitter in Yankee Stadium that hits both lefties and righties well, I think that he could certainly surpass that number, although even such a conservative projection shows a reason for optimism and an increase in power after last season’s outage.
With that said, if Johnson’s OBP is .426, like it was in ’09, I doubt anyone will mind if his ISO is around .115 or so.
Note – Turkenkopf later updated his findings with an added methodological change that alters the difference between projected ISO and actual ISO, but there is still a drop.
Photo by the AP