TL; DR: Spring training stats have some meaning, but Moose has shown up in March only to falter in April before.
So it's spring again and Moose is tearing the cover off the ball in Surprise, Arizona. I got to go to the game last Friday, and while it was free of rally-killing home runs, Moustakas did look impressive lacing the ball into right field.
I don't think anyone expects outstanding Spring Training performances to continue into the regular season, but I thought it would be interesting to see how the pre-season stats match up against the regular season. The data set I used was just 2013 Spring Training and the 2013 regular season, limited to batters with >50 PA in spring and >200 PA in the regular season. This pretty much limits the data to major league players.
As shown below, the relationship is tenuous but statistically significant. with SLG and OPS as better predictors, unsurprisingly, than batting average.
I added four Royals' pre-season stats that I remembered being particularly good. Remember when Lorenzo Cain led the league in OPS for most of the 2012 spring? My fantasy team remembers when he got cut pretty quickly after the draft.
Sure enough, both Moose in 2013 and Hosmer in 2012 fell short of what we might expect them to do in the regular season, based on their torrid Spring Trainings in those years. Gordon in 2012 had a great Spring Training and an even better (in relative terms) regular season. Cain ended up right about where we would expect him.