Home Run Regress? Granderson Edition


I love Curtis Granderson.  From the moment the Yanks traded the raw and limited Austin Jackson, for the already polished and well rounded Granderson, I knew it was a match made it heaven.  Between speed, defense, patience, and LH power, Curtis was going to excel as a Yankee.  The short right field porch was also seemingly going to boost his power and homer total.  


Before 2011, Granderson was never a huge homer threat, evidenced by hitting 102 bombs in about 2,900 PA's as a Tiger, about a 3.5% clip.  However, as a Yankee his power has exploded, slugging 65 homers in just over 1,200 PA's, a 5.3% clip.  While Yankee Stadium has a lot to do with this increase in homers, there are some worrying trends that might suggest 2011 was Grandy's peak power year.  Let's look at Curtis' 2011 numbers to see if he can slug another 40 in 2012.  


41 Home runs is a boatload on today's post-steroid game, Granderson's 41 ranked 2nd in all of MLB behind just Jose Batista's 43. Often when players hit an inordinate amount of homers in a year (Granderon's 41 is 11 more than his previous career high), there is often an element of luck that factored into the total.  We can look at some batted ball data, and hittrackeronline.com to see what kind of homers he hit and if they are repeatable. The first number that jumps off the charts is Granderson's HR/FB%.  Last year he put up a 20.5% figure, 6.6%, or about a 33% increase from his career average of 13.9%.  League average is about 10.6%, so to almost double that figure raises some red flags.  As we know regression to the mean is an ever present factor in the game, so almost certainly we would expect his 2012 HR/FB% to mirror his career number of 13.9% going forward.  Yankee Stadium has obviously had some effect so lets use his Yankee career HR/FB% of 17.5% as a better measure.  I'm not wishing regression on Curtis, but it seems inevitable, a 3% regression means more outs and less home runs.  Also, the fact that his Flyball % stayed right around his career average, we can assume many of the fly balls he hit last year will turn into outs.  Adjusting for regression in this area can account for a 3-4 HR decrease in 2012.  


Next we need to look at what type of homers Granderson hit last year.  Of course all home runs are scored equally, but not all are hit the same, or will leave each ballpark in different circumstances.  Hittrackeronline.com measures HR distance, trajectory, speed, apex, etc.  It is definitely the best source out there for tracking homers.  HTO groups home runs into categories:


"Just Enough"- Means the ball cleared the fence by less than 10 vertical feet, OR that it landed less than one fence height past the fence. These are the ones that barely made it over the fence.


"No Doubt"- Means the ball cleared the fence by at least 20 vertical feet AND landed at least 50 feet past the fence. These are the really deep blasts.


"Plenty"- Everything else, except for the 2 above Home run types


"Lucky"- A home run that would not have cleared the fence if it has been struck on a 70-degree, calm day.


It goes without saying that the best and most consistent HR hitters hit lots of no doubters and plenty's.  The more just enough and lucky homers, the more likely those home runs are going to become outs the following year.  Let's see how Curtis measured up in each category.  


Just Enough- 8, No Doubt- 11, Plenty- 17, Lucky- 5


While Granderson lead the Yankees in each category due to his total HR output, the number of Lucky HR's is scary.  Granderson lead all of MLB with 5, which screams regress.  Only 4 players total hit more than 3 lucky HR's, so it is rarefied but not pleasant company.  While luck is an inherent factor, and an ever present one, we can't assume he won't hit some lucky HR's in 2012.  However, we can almost guarantee it will not be 5+.  If we estimate a more realistic figure of 2-3 lucky homers, which would still place Granderson near the top of that not-so-distinctive list, that's still a 2-3 HR decrease from 2011.  If we combine that 2-3 HR difference due to luck with the 3-4 HR difference due to his inflated HR/FB%, we're looking at a HR total of around 34-36.  I think this is a much more realistic figure given his career numbers, improvement in his swing due to Kevin Long, and his move from spacious Comerica to cozy Yankee Stadium. 


So while many people expect Curtis to belt another 40 home runs and be one of the biggest power threats in the game once again, I see room for regression to a more realistic homer total of about 35 in 2012.  While this seems marginal, the value of a HR is so great that a six homer difference could change a few games for the Yanks in 2012.  


- Alex Bardani


References: Fangraphs, Hittrackeronline.com