In my view Clevinger is a very impressive prospect who deserves far more national attention than he's received. Last year for Double-A Akron he posted a 2.73 ERA in 158 innings with a 145/40 K/BB and just 127 hits allowed.
From the 2016 Baseball Prospect Book:
Mike Clevinger, RHP, Cleveland Indians
Bats: R Throws: R HT: 6-4 WT: 225 DOB: December 21, 1990
2012: Grade C; 2013: Grade C; 2015: Grade C; 2015: Grade C
Originally a fourth round pick of the Angels in 2011 from Seminole Junior College in Florida, Clevinger had Tommy John surgery in 2012 and fell off the radar for a while. He had his stuff back in 2014 but his command was inconsistent. The Indians got him in a trade for Vinnie Pestano, then Clevinger took off in 2015 with a dominant performance in Double-A. There’s a lot to like here: low-to-mid-90s fastball, plus slider, solid curve and change-up, and greatly improved command last summer. He’s got the Jake deGrom thing going with the long hair look and similar height, though deGrom is more athletic and Clevinger’s stuff isn’t quite as electric. It is still plenty strong however, his command has turned into a real asset, and he has a reputation for pitching well under pressure. Clevinger should be ready for a trial in 2016 and could become a number three starter, maybe even more. Grade B+.
Clevinger opened with Triple-A Columbus, making seven starts with a 3.03 ERA and a 36/17 K/BB in 36 innings with 28 hits allowed. Nothing he has done this season has changed the view from back in February, except he's shown he can get Triple-A hitters out, too.
He showed that last September actually, throwing 7.2 no-hit innings in the International League playoffs.
On my Top 175 MLB Prospects for 2016 list, I ranked Clevinger at 28th overall, 13th among pitchers. This was an aggressive ranking and generated some controversy, many seeing Clevinger as more of a Grade B type rather than a B+/A-, in part due to his age. I can understand that view, but this is an intuitive call.
The key thing to look for in his first start: command. His walk rate at Columbus was higher than ideal and major league hitters may lay off stuff that Triple-A hitters would chase.