If there's one area of the Twins roster that you can look at and feel completely comfortable, both now and going forward, it's the bullpen. On the left-handed side, their best arm is the closer, but they also have Brian Duensing and Caleb Thielbar, with Pedro Hernandez also offering some potential. In terms of right-handers, there's Jared Burton and Casey Fien topping the depth chart, with Anthony Swarzak anchoring the long role.
That's six relief jobs that you can already consider claimed for next year, meaning that there will probably be only one opening available for the taking. With Josh Roenicke outrighted and likely out of the picture, many contenders stand in line to join the bullpen as useful right-handed relievers, both in the immediate future and down the line. Let's take a look at them.
Michael Tonkin, 23
Tonkin's outstanding major-league debut this season flew under the radar, at least from my perspective. He came up for one appearance in July, then another in August, and got a more extended look in September at a time when many fans had stopped paying attention. I personally saw Tonkin pitch maybe twice in the final month, because I was watching fewer games at that point and, when I did watch, I often tuned out after the Twins fell into an early hole. (Interestingly, Tonkin made nine appearances this season and didn't pitch in a single winning effort.)
Tonkin didn't pitch quite as well as his stellar 0.79 ERA suggests, because he also allowed five unearned runs, but his peripherals were solid (1.06 WHIP, 10/3 K/BB ratio in 11 1/3 innings) and he flashed a powerful fastball that averaged nearly 95 MPH. He has established himself over the past couple seasons as the organization's best relief prospect, with setup or even closer potential, and is easily the favorite to claim the open spot in next year's bullpen.
Ryan Pressly, 24
That Pressly spent the entire 2013 season in the majors was more a function of necessity than his performance. The Twins needed to keep the Rule 5 draftee on the 25-man roster all year long in order to keep him in the organization and, to his credit, Pressly made it fairly easy to do so. Over 49 appearances he totaled 76 2/3 innings, operating as a hybrid middle/long reliever and achieving solid results with a 3.87 ERA and 1.28 WHIP. Based on his lack of strikeouts (5.8 K/9) and his mediocre control (3.2 BB/9) it's tough to see the right-hander maintaining that effectiveness long-term unless he makes noticeable improvements, but at least the organization will be able to keep him around and figure what they want to do with him.
There's been some talk of moving Pressly back into a starting role, even though he struggled mightily as a starter in the minors before being transitioned to the bullpen.
A.J. Achter, 25
It's unknown whether Achter will eventually make an impact in the majors, but he has already easily surpassed his draft status simply by emerging as a legitimate prospect. A 46th-round pick out of Michigan State University back in 2010, Achter has registered a 3.17 ERA in four minor-league seasons while averaging 9.6 K/9. This year, he pitched well enough in the first half at New Britain to earn a promotion to Rochester, where he finished with a 3.04 ERA in 16 appearances. Now, the 25-year-old is participating in the Arizona Fall League, where he has a chance to further establish himself as a contender to join next year's relief corps. His biggest obstacle at this point is command; in 60 1/3 innings between Double-A and Triple-A this year, he issued 33 walks.
Zach Jones, 22
Joining Achter in the AFL is Jones, who is farther away from the majors but also possesses considerably more upside. Acquired in the fourth round of the 2012 draft, Jones has barely gotten his pro career started but has already demonstrated the ability to dominate, with 104 strikeouts and a 1.97 ERA in his first 68 2/3 innings in the Twins organization. Much like Achter, he needs to refine his control (5.1 BB/9 rate), but he has proven almost unhittable as opponents batted just .172 against him this year in Ft. Myers.
Trevor May, 24
This name is a bit of a wild card in that May has worked as a starter for nearly his entire career, and the Twins are surely hoping he can continue to develop in that capacity, but many believe his long-term future is as a reliever. May certainly has MLB-caliber stuff but his command and stamina have been lacking and he didn't do enough this year in his second turn at Double-A to alleviate any such concerns. In 27 starts with New Britain, he averaged just 5 2/3 innings per start. From a 24-year-old repeating Double-A, you would certainly like to see more consistently deep outings.
As a reliever, May could maximize his strengths while better hiding his weaknesses. But of course, with their dire shortage of starters in the high minors, the Twins will likely show patience with him in his current role for the time being.