1. Scott Diamond. He's gone through some struggles recently, with a 6.64 ERA over his past four starts, but that was to be expected. In addition to the fact that he was bound for some regression, he might be wearing down with 183 innings pitched this season. Nevertheless, he's clearly at the head of the pack.
2. Sam Deduno. Against all odds, the 29-year-old continues to turn in quality starts despite an ugly 48-to-43 strikeout-to-walk ratio. After tossing a dud against the Rangers on August 24, he's bounced back with a 1.80 ERA in three starts since. Most impressive, he's struck out 18 and walked only six in 20 innings during that span.
3. Cole De Vries. He's done for the season after suffering cracked ribs on a comeback line drive last week, but De Vries has seemingly positioned himself well by turning in a solid 4.11 ERA and backing it up with decent peripherals (outside of his ugly homer rate). Still, it's difficult to trust his stuff.
4. Liam Hendriks. The rookie's path to becoming a better pitcher is clear: attack the strike zone more and bring down that .350 BABIP. He's continued to struggle in both areas since rejoining the rotation, but at least he's dialed down the long balls since his earlier stint.
5. P.J. Walters. After a fairly impressive stretch earlier in the year, he spent two months on disabled list and in two starts since returning he has been flat-out terrible. Still, his performance when healthy should be enough to merit another shot in Rochester next year.
6. Esmerling Vasquez. His strong performance in Triple-A earned him a September call-up, but two putrid outings since joining the Twins – in addition to the fact that he's been used almost exclusively as a reliever in the minors lately – confirm what we already thought: he's not equipped to start in the bigs.
7. Kyle Gibson. Among pitchers not currently in the rotation, Gibson has to be the most likely candidate to claim a spot out of spring training next year. He pitched well in a short minor-league rehab stint this year and will hopefully be fully on track after throwing in the Arizona Fall League.
8. Brian Duensing. His struggles as a starter (6.92 ERA) and success as a reliever (2.98 ERA) should have the Twins convinced of what his role needs to be.
9. Anthony Swarzak. Like Duensing, Swarzak is clearly meant to be pitching out of the bullpen. He's a useful long reliever but nothing more than an emergency spot starter.
10. B.J. Hermsen. Dark horse for a rotation spot next year? Probably not, as the Twins aren't apt to rush young prospects, but the 22-year-old's long track record of success – which continued this year as he posted the fifth-best ERA in the Class-AA Eastern League despite younger than anyone in front of him – cannot be ignored.