Where did Lance Berkman's power go?
2001 slugging percentage, extra base hits: .620, 94
2002 slugging percentage, extra base hits: .587, 79
2003 slugging percentage, extra base hits: .515, 66
For one thing, he had trouble hitting at home at Minute Maid Park in 2003: 884 OPS, 11 HR's - both way down from previous years.
Also, it seems that he's been putting in extra time working on batting right-handed against lefties. Unfortunately, this has had the adverse effect of his splits while batting left-handed go down:
RH OPS, LH OPS
The only problem with Lance concentrating on working on batting right-handed is that over 3/4 his at-bats are as a lefty. I'm guessing that his RH OPS was so low in 2002 that he (and others) decided that he had to improve in that area. However, you shouldn't always work on eliminating your weaknesses; sometimes you should just focus on your strengths.
Mathematically, it's not worth it for Lance to raise his RH OPS 169 pts if his LH OPS drops 86 points, simply because the great majority of his at-bats are as a lefty. I admit that there's a chance that some of his more important at-bats will be as a righty because teams will bring in a lefty to pitch to him, but (on the other hand) the Astros might not even have as many 'important' at-bats if Lance doesn't get his power back. Hopefully Lance will get back to what he was doing in 2001, and have a huge year.