Dallas Keuchel was drafted in the 7th round of the 2009 MLB draft out of the University of Arkansas. He immediately started his career in low A and steadily moved up the ranks. Like a lot of other college pitchers without much upside, he had challenges in AA and AAA, but would post better numbers the second year in those levels (Barry Enright, anybody?). Keuchel made his MLB debut on June 17th of this year against the Rangers and has been a mainstay in the rotation since.
I'm not sure why, but Brooks Baseball does not have info on Keuchel's repertoire (perhaps not enough data?). However, according to Fangraphs, Keuchel's main pitch is his mid to high 80's sinker (35%) and also throws a mid to high 80's 4 seamer (22%), mid 70's changeup (17%), low 70's curveball (14%), and a mid 80's cutter (11%). According to a tweet by Keith Law from a couple months back, he sees Keuchel as a backend starter at best. Law also refers to him as a "sinkerballer with control but no out pitch", and Keuchel's minor league numbers back up that assessment as he averaged only 5.9 K/9, but also had a good 1.9 BB/9.
Keuchel made his 5th career MLB start against the Dbacks on July 21st and got absolutely HAMMERED! He only lasted 3 1/3 innings, giving up 7 hits, 7 runs (6 earned), while walking 4, striking out only 1, and giving up 2 home runs to Jason Kubel. It seems like lately sinker ball pitchers have been giving Dbacks hitters trouble (Wainwright, Lohse), but the fact that Keuchel does not have an out should bold well for the Dbacks. In my opinion, a pitcher that has been pitching as poorly as Keuchel would be sent back down (currently posting a 5.29 ERA/5.80 FIP), but the fact that the Astros are rebuilding, on their way to possibly having the worst record in MLB history, and don't have any options for their staff is the reason why he's still in the majors.