Minor League Prospect Note: Trevor Rosenthal, RHP, St. Louis Cardinals
The St. Louis Cardinals promoted right-hander Trevor Rosenthal to the majors today.
Shelby Miller was supposed to be the big right-handed pitching hope for the Cardinals this year, but he's busy scuffling in Triple-A. Rosenthal, meanwhile, was doing a fine job for the Double-A Springfield Cardinals in the Texas League, with an 8-6 record in 17 starts, a 2.78 ERA in 94 innings, with an 83/37 K/BB and just 67 hits allowed. He will be used in the bullpen for now, but in the long run he's got a shot at being a starter.
Rosenthal was drafted by the Cardinals in the 21st round in 2009, from Cowley County Community College in Arkansas City, Kansas. Although he posted a 4.11 ERA in 22 starts for Low-A Quad Cities in the Midwest League last year, the ERA was deceptive and his component ratios were quite strong: 133/39 K/BB in 120 innings, 111 hits.
He rated as a sleeper prospect pre-season and has certainly woken up very nicely, thanks to a 91-95 MPH sinking fastball. He hits the upper 90s at times, with some scattered reports of hitting 100 on occasion. He also has a very good slider. His changeup comes and goes, and the development of the third pitch will determine if he starts or relieves in the long run. I think he has sufficient proficiency to develop it, but easing him into the majors in a bullpen role makes sense for now. His arm action is clean, although his command can be inconsistent.
From a sabermetric point of view, note the following: his 3.04 FIP in 2011 was much better than his 4.11 ERA, but that's flipped this year, with a 3.51 FIP but a 2.79 ERA. In other words, he pitched better last year than his ERA at Quad Cities suggested, but he isn't pitching as well this year as his ERA at Springfield indicates. That said, 3.51 is still a good mark for pitcher in Double-A who skipped the preceding level, and reports on his stuff are quite impressive. He's thrown strikes very well lately (38/9 K/BB ratio in 41 innings over his last seven starts), and obviously the Cardinals feel that he is mentally and emotionally ready for the challenge.
Rosenthal is a solid Grade B prospect at this point, and further evidence that with good scouting you can find impressive pitching arms in the later rounds of the draft.