Dave Bush is fine as a #4 or #5 starter. The problem is that the Brewers have at least two, maybe three other #4/#5 types on their roster. As a free agent after this season, Bush was already a candidate to be replaced.
His start today against the Houston Astros isn't going to help his cause for a new deal with the Brewers.
I don't tend to get worked up over single games, so I really don't think I'm blowing this out of proportion. We've seen this before from Bush -- he cruised through the first four innings, allowed back-to-back hits to start the fifth, had the defense misplay an easy out, and unraveled from there. If this were a Manny Parra start, we'd be talking about mental toughness again.
By the time he left the mound, a 5-0 Brewers lead was a 5-5 tie and only one man was out. By the time the inning was done, he was on the hook for the loss. His WPA for this game was -.409, his second worst WPA performance of the season (and I bet you can guess which start was stinkbomb #1). For those that aren't up on Win Probability Added or anything else you can find on FanGraphs, the rough translation is that if the Brewers wound up losing the game, he would've been damn near the sole reason.
Bush has been a solid pitcher for the Brewers over his five seasons in Milwaukee. I'd go as far to say that he pitched well enough to make the Lyle Overbay trade look good from the Brewers' perspective, even though Zach Jackson never panned out. He'll always be remembered as the guy who started the Brewers' only win in the 2008 NLDS against Philadelphia. But it's time for him to go.
It wasn't that long ago that I was in favor of possibly offering Bush a cheap contract late in the winter if improvements couldn't be found elsewhere. Sign him up to the Braden Looper/Doug Davis Special -- essentially a one year deal with an option for a second year if you don't completely suck. At this point, I don't know if I'd even spend the $4-$5 million on him that kind of deal would require.
He was a pretty good pitcher the first couple years he was in Milwaukee, but he hasn't posted a WAR over 1 since 2007. Part of that is injuries. Part of that is just detoriorating skills. This year, FanGraphs had his WAR at 0 before this start. The only starters that have been worse this year are Doug Davis and Jeff Suppan.
He's the only one that's been allowed to keep pitching. He shouldn't be allowed to (at least for the Brewers) in 2011.