FG on Fox: Will 2015’s Rookies Suffer a Sophomore Slump?
2015 was an unquestionably special year in baseball: we witnessed teams that hadn’t made the postseason in 20 years break through the barrier, saw latent fanbases reborn, and finally, after falling just short in 2014, a magic-fueled, unconventional team won the World Series. Because of a mixture of player development trends and incredible fortune, we also saw something exceedingly rare: the best positional rookie class in the past century. The likes of Kris Bryant, Carlos Correa, Matt Duffy, and many others announced their arrival with exceptional first-year performances, taking the league by storm and bringing about a new golden age for young, ultra-talented position players.
We’ve stated many times how much better the 2015 rookie positional class was than any other in the past hundred years. The fact bears repeating again because of its magnitude. Below you’ll find a chart showing the average Wins Above Replacement for positional rookies for a full season of plate appearances (600 PAs) from 1920 to 2015:
As we can see, no other season is close to 2015. There are a few reasons for that, reasons that are complex and outside the particular scope of this article. For now, this should serve as background for what we’re discussing today: how sophomore/follow-up seasons compare to great rookie campaigns. We’ll be focusing specifically on the years that followed Rookie of the Year campaigns to try to discern whether a “sophomore slump” occurred among the league’s best first-year players, and we’ll also bring in the 2016 projections for our exceptional crop of 2015 rookies to look at next year’s expected performance.
