While not a pop-up prospect entirely (he ranked the 21st prospect in the deep Mariner organization in 2011 per Baseball America), Brandon Maurer certainly put himself on more maps in 2012 and has only gained steam this offseason. The main knock on Maurer has been an inability to stay healthy with an elbow injury in 2010 and shoulder problems in 2011. While no injury is good, those are not the joints (settle down Jonathan Singleton, we're not talking about those either) you want to hear about when discussing pitcher injuries. Maurer is a success story though, injury or not. He was signed in the 23rd round in 2008 and signed for a well above slot $150,000. Anytime you turn a 23rd round pick into what Maurer is today, that's a win for you scouting/player development unit.
So what exactly is Maurer today? He's an ideal 6'5/215 lbs and has the frame to log innings. His fastball sits in the mid 90s and can touch 97 MPH. The velocity is good, but what separates Maurer is the sink he gets on it. The sinker comes in a little less than maximum velo but the movement makes the dropoff worthwhile. He complements the fastball with an average slider that flashes plus and generates plenty of whiffs when it's on. While most pitching prospects would add in a developing change up and call it a day, Maurer also attacks hitters with an above-average curve featuring depth and break. He does have that developing change in his arsenal, but it comes in a little hard at times. Control is a strength for Maurer as he can pound the zone, but he's still refining his command and working on throwing quality strikes. The Mariners believe Maurer's health issues were related to conditioning and that as long as he stays on top of that, he'll be able to chew innings.
I also found these notes from Harry Pavlidis over at Baseball Prospectus helpful in regards to measuring Maurer's stuff via (small samples of) PITCHf/x:
PITCHf/x shows a relatively low, three-quarter arm slot. The righty is 6-foot-5, so he's still able to get tilt from that angle, turning the delivery into an asset.
His four-seam fastball was 95-96 mph, and his sinker came in a couple of ticks below that. Once again, the arm slot comes into play: His four-seam runs with a little sink and his two-seam shows enhanced movement with a few inches of added sink.
He threw one (85 mph) that didn't have slice, but it did show nice depth.
Spending all of 2012 at Double-A Jackson, Maurer was finally able to put that big frame to use and threw a career high 137 innings. While his 117 strikeouts in those innings might not blow you off the page, it's a solid K/9 for a projected mid-rotation starter and more impressive considering his 1.29 GB/FB ratio. As discussed, Maurer does a good job of pounding the strike zone as evidenced by his 3.1 BB/9. All of this is to say, when healthy, Maurer fires a heavy sinker that arrives in the mid 90s, keeps the ball low and has two above average secondary pitches and the potential for an average change up. He's not as polished as you'd like given the lack of innings but he's also only 22, so it's not like time has passed him by. He'll begin 2013 in Triple-A and, despite the Mariner's bevy of pitching prospects, will likely be among the first looked at in the even of an injury to an established starter.
Despite being in the organization for 4 years, Maurer has only thrown 371 innings and will benefit from added time in the minors this coming season. He has the talent to succeed at the major league level, and while he doesn't project as a frontline starter a 3/4 seems to be a reasonable outcome, provided his health is good. In fantasy, this means you shouldn't be drafting him unless your league features a minor league roster, but that he is a viable waiver wire claim should he get the call. He'll give you quality innings but nothing exceptional. If your expectations are reasonable, you'll receive a nice return on investment from Maurer.
Minor League Central