That's a bit too broad. Soriano had plenty of cold streaks/slumps/whatever you want to call them during the two months the Cubs were dominating because he is and always has been a very streaky hitter. Yes, he's missed now, but his injury combined with Lee's slump and Aramis being hurt/out is the much larger issue. If the latter two weren't happening, or even just one of them was mashing, Soriano's absence wouldn't be nearly as obvious.