Sounds counter intuitive but if you look at his fangraph data, Javy's contact rates are not what has changed, while his HR/FB ratio is way down from his better years, so you can make a reasonable argument that he is not hitting the ball as hard when he hits it.
I think we spend too much time fretting over Javy's zone control. That is all about pitch recognition and there is little a hitter can do change his ability to see the ball, all he can do try to get better hitting what he swings at - no matter where the pitch ends up. And strength to get the bat to the ball is a piece of that.
Now that said, you can get quicker to the ball, which helps with the recognition problem, and I think Javy does have a fair amount of excess wind-up in his swing he might work on eliminating and if he comes so ST without any changes in his swing I won't be optimistic regardless of what he accomplishes in the weight room.