What Do the Phillies Have in Aaron Altherr?
Last night, Aaron Altherr finally got going after his trip to the disabled list. Altherr smashed an upper-deck go-ahead grand slam off Clayton Kershaw, the best pitcher in baseball. As it stands now, Altherr has been worth 1.3 fWAR in about a half a season of plate appearances, bashing 17 home runs and producing a 125 wRC+. It’s been a good bounce-back season for the Phillies’ outfielder, but he again missed time with injury.
In Spring Training last season, Altherr tore a ligament in his wrist; he didn’t make his season debut until late July, and once he returned he was clearly not the same player who put up 1.8 fWAR in just 161 PAs in his rookie year. In July of this season, he injured his hamstring and was sent to the disabled list. He returned from that injury too soon and reinjured it, leaving him out of the lineup until September 9.
Despite negative defensive numbers bringing down his value this year (possibly tied to the hamstring injury), Altherr has proven himself worth a starting outfield job for the Phillies next season. The question is, then, can the Phillies count on him to stay healthy going forward? They say the best indicator of future injury is past injury, and Altherr has quite a few of those in his young career.
I decided to look at some comparable players to gain some sort of perspective on what we can expect of Altherr going forward. Obviously, all players are different, and Altherr could play the next ten seasons with perfect health, but it’s important to ground your projections with precedent. With that in mind, I looked at seasons since 2000 where a player in Altherr’s age range (25-27) posted a comparable wRC+ (120-130) in a comparable number of plate appearances (300-400). This search gave me 20 names, including Altherr and four other players this season:The average player in this sample played 15 more games in the following seasons, but at only 422 PAs, they were far from iron men. It should be noted, however, that the players who continued to produce above-average wRC+ managed to stay on the field for an average of 126 games and 517 PAs per season. This indicates that some of the limited playing time may be performance-related, rather than injury-related. You could argue though, that the decreased production could be attributed to injuries as well, and Altherr has already suffered the results of injury-related struggles last season.
These results are concerning, especially when sorted into buckets:Almost half of the sample was worth less than a win per season over the next three seasons. That’s not good. And looking at the highest-achieving bucket, there’s not a lot of similarities to Altherr. Josh Hamilton, as you may have heard, struggled with drug addiction until his Major League debut in 2007. He entered the season as a Rule-5 draft pick and immediately succeeded. His career was later marred with injuries including a rib injury that sidelined him for much of the 2009 season, but he managed to put up an 8.4-win season and an MVP in 2010. However, the circumstances surrounding his early career are entirely different from Altherr’s.
Angel Pagan may be the success story most similar to Altherr. He missed time with injury in every season between 2007 and 2009, but came back to produce a 5-win season in 2010 and a 4.7-win season in 2012 sandwiching an entirely mediocre 2011. Dustin Pedroia is unlike Altherr in that his 2010 season is the only season he played less than 135 between 2007 and 2014.
Matt Carpenter, likewise, only missed time in his rookie season. He still played in 114 games that season, more than Altherr has in a single season, and hasn’t played in fewer than 129 games in the 5 seasons since. Carpenter and Pedroia are the two players who played the most in the following seasons, and their careers aren’t especially similar to Altherr’s so far.
This is far from a definitive analysis, but the returns on players with early career injuries, even if they produce in their limited opportunity, are not great. The Phillies should still start Altherr on Opening Day, but history shows that they should be prepared with a good fourth outfielder.