If you aren't an Arizona Diamondbacks fanatic, or if you blinked at the wrong time, you might have missed the fact that unknown prospect Mike Bolsinger appeared in five games (four starts) in the majors already this spring. It didn't last long: he got knocked around in his start against the Milwaukee Brewers last Monday and was sent down to Triple-A Reno on Tuesday. In 23.2 big league innings before his demotion, Bolsinger posted a 6.08 ERA, giving up four homers and 33 hits. He did post a decent 22/8 K/BB ratio.
Who is this guy and will he get another chance?
Bolsinger was a 15th round pick in 2010 from the University of Arkansas. He was generally successful in college and remained so at the lower levels of professional baseball, posting a 2.40 ERA with a 140/38 K/BB in 140 innings at the A-ball levels. He held his own in Double-A (3.35 ERA, 95/53 K/BB in 121 innings) and Triple-A (4.35 ERA, 110/44 K/BB in 120 innings) which is actually solid for the difficult pitching environment at Reno and the Pacific Coast League.
Despite his track record, Bolsinger doesn't rate as a hot prospect. His fastball tops out at 90 and is usually in the mid-to-upper-80s. His best pitch is his curveball, which often flummoxed minor league hitters. It didn't work consistently well in the majors, however; it can fool them the first time through a lineup, but once hitters get a look at him he's vulnerable to big innings.
Bolsinger is still a nice asset for an organization: he's an effective Triple-A staff stabilizer who can see work as a fifth starter in an emergency. It wouldn't surprise me if he has a surprisingly good year in relief at some point, if used in the right spots when his command is locked in. He's a Grade C guy, but handy for organizational depth.