Following up on my piece about Pirates who could take a step forward next year, here's another about players who could take a step back from their 2005 performances. (Keep in mind, again, that I'm defining "collapse" as a serious regression from a player's 2005 performance, not in relation to a projection.)
1. Roberto Hernandez (2.58 ERA in 2005). 41 year-old reliever. 2.58 ERA. Enough said.
2. Chris Duffy (.341/.385/.429 in 2005). Duffy simply isn't this good. He isn't young, and he climbed the minor league ladder slowly, posting stats that were not nearly as impressive as what he did in a couple months in the majors in 2005. In addition, while Duffy has always been a high-average hitter, he never hit higher than .317 at any level before hitting .341 in the majors last year. That batting average is going to come down. Duffy will still be a fine defender next year, but I'm not sure that will be enough for Duffy to remain a productive player.
3. Zach Duke (1.81 ERA in 2005). I love him, of course, but nobody is this good. I'm not particularly concerned about the difference between his ERA, which is off-the-charts great, and his peripherals, which are only good - Duke had that 'problem' in the minors, too. My concerns are more general - young pitchers tend to get hurt and have bouts with ineffectiveness, and, again, no one is this good.
4. Paul Maholm (2.18 ERA in 2005). Maholm's performance in a small sample in the bigs is out of line with not only his peripherals, but his history of minor league performance - he posted a lower ERA in 2005 in the majors than he did in either Class AA or AAA. To paraphrase one writer's line about Tike Redman, if Maholm's improvement is the result of his 'learning something,' he appears to have done so on the flight from Indianapolis. (You could also say that about Duffy. Maybe U.S. Air has a particularly baseball-savvy flight attendant.)
5. Joe Randa ( .276/.335/.452 in 2005). Randa completely fell apart in the second half of last season after he moved from Cincinnati to a pitchers' park in San Diego. He's also 36, around the age when players with his skill set usually ride off into the sunset.
6. Sean Casey (.312/.371/.423 in 2005). Yes, he appeared on my list of potential breakout candidates, too, but Casey is a high-risk player. He's injury-prone, he isn't in great shape, he's on the wrong side of 30, he's slower than a Kiyoshi Kurosawa film, and a lot of his value is tied up in batting average. All those things are warning signs.
7. Jeromy Burnitz (.258/.322/.435 in 2005). Not to pile on here, but when you sign a bunch of players in their 30s and 40s, you take big risks. Burnitz' move to the insane offensive environment in Coors from tough pitchers' parks has partially masked the fact that he has been declining for a while now. He's not a good contact hitter in the best of circumstances, and as his decline continues, he's not unlikely to put up some Mendoza-line batting averages. If that happens, his power won't save him.
8. Salomon Torres (2.76 ERA). On one hand, Torres was simply superb after the 2005 All-Star break (as WTM points out), posting a 2.04 ERA with 42 strikeouts and 17 walks in 53 innings. On the other, his final peripherals were much worse than his ERA, and he'll be 34 this season. If I had to bet, I'd say he'll take a step backward this year, but not a huge one.
Ultimately, I feel a lot more confident in this list than in the breakout list. Casey is #6 on both lists, for example, but it's a lot more likely that he'll collapse than break out. The Pirates have a lot of players this year who could fall apart fast. If they're going to seem competitive this year, they have to hope that doesn't happen.
Again, feel free to add your own players or argue with mine in the comments.