There are a lot of relievers on the market. The Brewers have been linked to George Sherrill and Huston Street, most prominently, and the fact that the Pirates were scouting Huntsville suggests that we could've been in on Damaso Marte. (Marte was traded to the Yankees yesterday.)
Adam McCalvy reported yesterday on some complaints that Melvin was standing pat, ignoring our "need" for bullpen help. With guys like Marte changing addresses, any team could improve their bullpen, but of course, these things come at a certain cost.
Melvin also made a comment recently that he isn't worried about the bullpen so long as the rotation keeps pitching the way they have. It's easy to laugh, but there's a lot of truth there.
We've seen quite clearly what Sabathia can do--he's average more than 8 innings in his four starts so far. It's probably optimistic to expect him to keep that up, but he's certainly going to give us more innings than we could expect from Bush or McClung--whoever would be pitching if we hadn't gotten CC.
Let's try to stick some numbers on this. Over the entire season, CC has averaged a bit more than 7 IP per start. NL offenses aren't as strong, so I feel comfortable rounding up--at least to 7.3, maybe even to 7.7. He's not going to throw a complete game every time out, but it's tough to imagine needing more than one or two relievers in a game that CC starts.
By contrast, Bush has averaged a bit over 6 IP in his starts, and McClung goes about five and a half per outing. Combined, they average out to 5.92. Keep in mind that CC essentially took the place of the bad one (the bad half of the platoon, or whoever would've slotted in if someone got hurt), so round down to 5.7 per start.
We've gotten 4 starts already from CC, and we're going to get at least 12, maybe 13 more. In those 4, he gave us 33 innings; in the next 12, we can expect 88, for a total of 121.
Assuming 5.7 IP per start, McBush would've given us about 91 frames in those 16 starts. It's worth considering, too, that the relief innings necessary would've been more variable--it's much more likely that McClung would give out after four innings than CC. I'm going to ignore that, though.
So, put it all together: Aside from the fact that we replaced a bunch of starter innings with better starter innings, we replaced *thirty* bullpen innings with that many innings from CC. If we got somebody like Sherrill or Street, we probably wouldn't get more than 30 frames from them--not if we had picked them up when we made the CC deal, and certainly not if we acquired them right now, with a bit more than 1/3 of the season left to play.
Not only that, but relievers--especially someone like Sherrill, not so much Street or Marte--are much more variable. CC has an impressive track record--short of a freak occurrence, we can take those 30 extra starter innings to the bank. Sherrill? We'd probably get 20-25 innings, but I don't think I need to tell a bunch of Brewers fans just how a bad a previously strong reliever can be in a half-season.
Good relievers are expensive, especially at the deadline. We have CC, a healthy Ben Sheets, and a 3-4-5 that has proven they'll chew up innings even on most of their bad days. Our starters have thrown more innings than those of any other NL team, and that's without much from Sabathia. Just about every other contender needs relief help more than we do. Let's allow them to overpay instead.