Closer - Joe Nathan
Nathan has been, arguably, the best closer in baseball since he took up that role for the Twins in 2004. Over the past 4 seasons, he's averaged 40 saves and a 92% conversion rate, with an ERA under 2.00 and K/9 over 10.00. After having his best season in 2006 (12.51 K/9!), the numbers dipped in 2007, particularly the strikeouts (9.67 K/9). The first sign of decline, or just an off year? The Twins, having just signed Nathan through 2011, are banking on the latter. Through 11 spring innings, the K/9 was up to 10.64. Whatever the K/9, I'd rather have him than Joe Borowski or Todd Jones.
Best case: a repeat of 2006
Worst case: he gets hurt
SfC projection: 70 IP, 2.10 ERA, 1.00 WHIP, 40 SV
Setup - Pat Neshek
When the bullpen imploded last May due to injuries and/or ineffectiveness, Neshek became Gardy's most trusted middle reliever. He was called into just about every sticky situation the Twins found themselves in, and was so effective that he nearly made the All-Star team. He declined steeply after July, probably due to overuse (he accumulated 74 IP despite being shut down with a couple weeks left in the season). This season, he's come back in better shape, and the hope is to use him more judiciously anyway. He could hardly have had a better spring (11 IP, 0 ER, 2 H, 0 BB, 9 K), so his prospects for this season look excellent.
Best case: the first half of 2007 lasts all year
Worst case: he gets hurt
SfC projection: 75 IP, 2.00 ERA, 0.90 WHIP
RHP - Matt Guerrier
I credit Guerrier with keeping the Twins in the race as long as they were last year. Merely the long-relief guy in his first couple years on the team, he had to step into the Jesse Crain/Juan Rincon roll last year, and responded by having his best season. He gave the Twins 88 IP, 2.35 ERA, 1.05 WHIP, and drastically improved his BB/9 and K/9. Most of the great numbers happened in the first half - the second half was closer to his career averages so far. With Crain returning from surgery, and Rincon hoping to recover his old form, the Twins might like to move Guerrier back to long relief. But until those guys prove their effectiveness, I wouldn't be surprised to see Guerrier used as the primary 7th inning guy next month.
Best case: 2007
Worst case: It's an off year
SfC projection: 85 IP, 3.20 ERA, 1.20 WHIP
LHP - Dennys Reyes
After putting up ERAs in the mid-4.00s and WHIPs in the 1.60 range for most of his career, Reyes came out of nowhere in 2006 to lead the Twins' bullpen with a 0.89 ERA. That number was shaped a great deal by how he was used, but he was undeniably effective, striking out about a batter per inning and issuing the fewest walks per IP of his career. He came crashing back to reality in 2007, though he was hampered by an injury in the early part of the season. This spring, I've mainly been concerned with his control - he's got to get ahead to be effective. In 10 spring IP, though he's given up 12 hits, he's only walked one batter, and so he's been able to escape his jams and put up a very encouraging 1.80 ERA. Considering he'll be used almost entirely against left-handed batters, his chances for success are pretty good.
Best case: 2006 Reyes
Worst case: Pre-Twins Reyes
SfC projection: 50 IP, 3.85 ERA, 1.35 WHIP
RHP - Juan Rincon
Rincon has been with the Twins throughout their successful run this decade. He peaked in 2004, when he appeared in 77 games and threw 82 IP, with a 2.63 ERA, 1.02 WHIP, 106 K and only 32 BB. He had been steadily declining until last season, when he declined precipitously. He put up career worsts in IP, ERA, WHIP, K/9, BB/9 and, perhaps most alarming, HR. The 9 bombs he served up in 2007 equalled the combined total of 2004-2006. And yet, he was offered a contract and is back for one more season. He was embarassed by his performance last year, and will be a free agent after the season, so he's got every incentive to show what kind of pitcher he really is.
Best case: Back to the good old days
Worst case: The decline (gulp) continues
SfC projection: 75 IP, 3.85 ERA, 1.35 WHIP
RHP - Jesse Crain
Crain had been one of the Twins' most effective relievers, even generating some discussion of being a future closer, until he broke down last season with a serious shoulder injury. His labrum and rotator cuff have been repaired, but it's difficult for any pitcher to get back to form after damaging those areas. Though Crain is in as good a condition as anyone in his situation could possibly be, it's still very uncertain as to how he will perform this year. Like Liriano, they'll have to take things slowly, and hope for the best. I wouldn't be surprised to see him in lower pressure situations this year.
Best case: good as new
Worst case: never the same
SfC prediction: 50 IP, 4.50 ERA, 1.35 WHIP
RHP - Brian Bass
Bass found his way onto the roster this spring because the Twins wanted 12 pitchers, he pitched well last year in Rochester and had a great spring, and he's out of options and the Twins didn't want to lose him. He'll be in the Matt Guerrier role from recent years, long relief.
Best case: Guerrier from 2005-2006
Worst case: back to the Minors (and therefore off the team)
SfC projection: 70 IP, 4.00 ERA, 1.40 WHIP
The Twins' motto this year could be: "Get Back to 2006!" and it seems especially true of the bullpen. Nathan and Neshek are going to be as dominant an 8th & 9th inning door-slamming duo as any in baseball. If Rincon, Crain, and Reyes can find their way even halfway back to their 2006 numbers, the Twins will have easily the best bullpen in the AL Central, and one of the best in the Majors. With a young, unproven starting rotation, they'll need it to be that good.