It occurred to me that this also might be caused by their hitting coach, if they had a new one. And guess what? They do...sort of. Last year on July 31, 2007, Wally Joyner became the hitting coach. Could that be what's causing the power outage? Does he have a "singles" philosophy?
Simply, no. First, Joyner wasn't just a singles hitter, although he trended that way at the late stages of his career. He regularly posted ISOs of .150 and higher. He hit for power in his early years, including 34 home runs in 1987, before the massive power increases of the early 90s. That figure was good enough to tie him for 3rd in the home run race that year. It seems unlikely he'd be teaching a singles approach.
More importantly, in August/September last year, the Padres slugged a higher percentage than they did before Joyner took over the hitting post. So it's probably just the excess of games in the home park.
But look at this table, showing where Padres hitters are hitting the ball in 2008, and their averages for 2005-2007:
Pull Middle OppField
2008 22% 57% 21%
05-07 28% 54% 18%
Padres hitters are pulling the ball quite a bit less, which saps power in a big way. Slugging percentages on pulled balls are in the .700s. Slugging percentages up the middle and to the opposite field are in the .390-.410 range. The Padres do not have a massively revamped lineup, so it should not be attributable to personnel changes. Again, this could be a ballpark effect.
Of course, there also are only 273 at bats in the 2008 calculation...far too small a sample size to draw definitive conclusions. It is something to watch, though, once we have more ABs to work with, and a more even distribution of home and away games for the Padres.
