Who is Minnesota Twins rookie Tyler Duffey?

Minnesota Twins rookie starter Tyler Duffey will take the mound this evening against the Tampa Bay Rays. This is his fourth big league start and the first three have gone reasonably well: 4.60 ERA in 16 innings with a 16/7 K/BB and a 1.80 GO/AO. We haven't discussed Duffey recently so let's remedy that oversight right now and get a read on his future.

Duffey pitched college baseball at Rice University. Used almost exclusively as a reliever, he posted a 3.06 ERA over three seasons (2010-2012), with a 189/55 K/BB in 153 innings with a 130 hits allowed. His junior season was particularly strong with a 1.93 ERA with a 68/21 K/BB in 51 innings, collecting seven saves.

Rice pitchers have a reputation for being very polished but also have a poor track record of staying healthy in the pros. In Duffy's case, the Twins saw him as a starting pitcher going forward and hoped that being used in a relief role in college would help him avoid serious health concerns. He was drafted in the fifth round in '12 and was sent to the Appalachian League for his debut. He was used in the bullpen for Elizabethton and performed well (1.42 ERA, 27/2 K/BB in 19 innings).

The starting pitching conversion began in 2013 and proceeded decently enough (3.64 ERA, 94/23 K/BB in 121 innings in A-ball), the best news being that he held up under the workload without trouble. 2014 was similar: 3.67 ERA, 113/30 K/BB in 150 innings split between High-A, Double-A, and Triple-A.

Although the numbers weren't radically different, there was a change in his scouting reports. Here's the summary I wrote for the 2015 Baseball Prospect Book:

SLEEPER ALERT!! Tyler Duffey was drafted in the fifth round in 2012 out of Rice University. He was a reliever in college, working with an 88-92 MPH fastball and a decent slider. The Twins liked his physicality and pitchability and decided to make him a starter. Rice pitchers have a reputation for burning out rapidly in pro ball. However, Duffey hadn’t been run into the ground in college, so the Twins figured that a gradual increase in his workload was doable. Getting used to his new role, he pitched adequately in 2013 but took a large step forward in ’14, boosting his fastball from 88-92 to 92-94 last year at New Britain. He still has the slider and has added a good change-up. While Alex Meyer and Trevor May get lots of attention as power arms ready for major league trials in Minnesota, Duffey isn’t far behind them and has a shot at being a good fourth starter. Keep an eye on him. Grade C+.

If you followed that advice, you've been rewarded with a fine 2015 season: 2.54 ERA in 22 starts between Double-A and Triple-A, with a 122/30 K/BB in 138 innings, 119 hits allowed, and a promising beginning to his big league career.

Age 24, Duffey is well-built at 6-3, 220 and has had no problems handling the conversion to the rotation. His fastball peaks at 94 and averages right around 91; he'll throw both a two-seam and four-seam variety. His breaking ball was identified as a slurvy slider by 2013 and 2014 minor league observers, but looks more like a curveball with bite this year. He still has the effective change-up and while his command isn't perfect, he has the pitchability and mound presence often associated with Rice products.

Assuming continued good health, Duffey looks like he can be an effective mid-rotation starter. He has little left to prove in the minors and should receive a full trial going forward.

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