by Daniel Gettinger
After last night’s game, Adrian Gonzalez has now hit 21 home runs in 2009. At his current rate, Gonzalez will finish the season with 66 home runs. He will almost certainly smash his previous season high of 36 home runs, set in 2008. The big question is whether Adrian’s power spike is real, or luck driven. The answer: a little of both.
Since Gonzalez came to the Padres in 2006, he has consistently increased his home run totals. In 2006 he hit 26 HR, he hit 30 in 2007, and 36 in 2008. This progression has been consistent with a typical course of power development. Gonzalez is now 27 years of age, somewhere around his prime. That he is having his best power season of his career is not a surprise. That he has hit home runs at such an astounding rate is.
The first thing I wanted to check was whether Gonzalez’s homers have been “lucky.” Have they barely snuck over the fence, or has there been no doubt about them. Greg Rybarczyk’s hit tracker tool helps us answer that question. Of Gonzalez’s first 20 home runs (the data for yesterday’s game has not yet been imputed), only four of them have been classified by Rybarczyk has having cleared the fence by “just enough.” Because approximately 1/4 of all home runs clear the wall by “just enough,” this metric does not predict any regression for Gonzalez. Adrian’s home runs have, in general, cleared the fence with plenty of room to spare.
So, if Gonzalez has not gotten lucky on his actual balls hit, why has he hit home runs at such a greater rate than in years past? Perhaps obviously, he has hit more a few more fly balls, and he has hit those fly balls harder than he has in the past. The following table captures Gonzalez’s fly ball rate, and HR/FB from 2006 to 2009.
What stands out is the huge increase in FB/HR in 2009. Some of the increase might be the result of added strength, or a more efficient use of existing strength, but some regression should be expected. In 2008, Jack Cust was the only player in the major leagues to hit more than 30% of his fly balls for home runs. And at 31%, he barely got there. 2007 was no different. Cust had a HR/FB rate of 33%. Nobody else was over 30%.
The rest of the HR/FB leader-board is full of high power guys who strike out a lot. Basically, they don’t make much contact, but when they do, the ball has a good chance of going out of the park. Gonzalez is not really that type of player. His K% is usually around 22%. Guys like Cust, Ryan Howard, and Adam Dunn, all of whom consistently have league leading HR/FB rates, strike out between 30% and 40% of the time. Combined with the fact that Gonzalez plays half has games at home run depressing Petco Park, and it appears unlikely that he will be able to maintain such a lofty HR/FB rate for the entire season.
Adrian Gonzalez is having a fantastic season. As he is in the prime of his career, we should not be surprised that he is playing better than he ever has. That said, I doubt Gonzalez will continue to hit home runs at such a ridiculous rate. His HR/FB rate is just not sustainable. My guess is Gonzalez hits something around 25 additional home runs in 2009. He might make a run at 50 home runs, but duplicating Sammy Sosa’s 1998 campaign of 66 home runs seems unlikely.