Mike Montgomery, Useful Pitcher

With both Hisashi Iwakuma and James Paxton on the disabled list, the Mariners’ starting rotation has been stretched to its limit. Both of these injuries weren’t exactly surprises as neither Iwakuma nor Paxton has been particularly durable during their careers. So heading into the season with Roenis Elias as the lone starting pitcher in Triple-A who could pitch competently in the majors seemed like a poor choice. Fortunately for the Mariners, there was one other starting pitcher down on the farm who has been able to contribute when called upon. Enter Mike Montgomery.

Mike Montgomery’s professional baseball career has been pretty rocky to say the least. He was a supplemental first round pick in the 2008 draft and quickly moved through the Royals minor league system for the first three years of his professional career. By that time, he was one of the top prospects in the Royals organization and ranked #19 in all of baseball. Once he reached Triple-A, the wheels fell off as he began to struggle with his command and his velocity. After two disappointing years in a row, the Royals gave up on him and included him in the Wil Myers trade after the 2012 season.

With the Rays, Montgomery never recovered the luster he had as a high draft pick and top prospect. He never regained his velocity and gained a reputation as a nibbler, living on the outskirts of the strike zone. When the Mariners acquired Montgomery from the Rays in exchange for Erasmo Ramirez, most of us were pleasantly surprised that the Mariners were able to receive anything of value in return.

Despite an arsenal that looks very different from his days as a top prospect, Mike Montgomery has transformed himself into something that might actually be useful at the major league level. He’s made four starts for the Mariners and has allowed just eight runs in those starts leading to a sparkling 2.73 ERA. His peripherals paint a different picture, however. His strikeout rate is well below average at just 11.3% and his walk rate is right around league average at 7.6% leading to a FIP that is almost a run higher than his ERA.

That K/BB ratio doesn’t inspire much confidence in his ability to be successful in the future. Let’s take a look at what his pitch arsenal looks like and maybe I can change your mind.

Montgomery mainly relies on a fastball with decent velocity for a lefty. He throws both a four-seamer and a two-seamer and they’re both average pitches. In the minors, most of his struggles stemmed from his poor breaking balls. His cutter is an evolution of the slider he threw as a prospect and it’s turned into a decent pitch. He throws it almost exclusively to lefties and is able to generate a whiff with it 30% of the time. His curveball hasn’t improved much though. He uses the curve more often than his cutter and it’s used to generate called strikes instead of swinging strikes.

His best pitch is his changeup and it might be the key to his success. He’s able to generate an above average amount of whiffs with the pitch and it’s helped him keep right-handed batters in check. The pitch has a ton of glove-side run to it, breaking away from right-handed batters. In fact, his changeup has the third highest horizontal movement among all left-handed starters in baseball this year. Since his changeup is his signature pitch, I took a look at some of the other left-handed pitchers in Major League Baseball who throw a similar changeup.

All five of these pitchers possess an above average changeup that makes up least 15% of their pitches. Tommy Milone and Jason Vargas actually are pretty good overall comps for Mike Montgomery. Their fastball velocity is a bit slower than Montgomery’s but their arsenal and their pitch mix are very similar and their results line up as well. Pitching in a friendly park with a good outfield defense behind him, Vargas has averaged around 2.0 fWAR over the past five years. Milone hasn’t been as good as Vargas (1.4 average fWAR over the past three years) because of a home run problem but the rest of his peripherals match up fairly well.

I’d guess that Mike Montgomery’s ceiling would be something like Vargas, a back-end starter who is able to thrive in the right environment, managing contact and limiting baserunners. Something like Tommy Milone would probably be the more likely outcome; a pitcher who serves as excellent depth for your rotation and can fill the back end of the rotation if there are no better options. Both of these outcomes are incredibly useful, especially for a team in the Mariners position.

We’ve seen Mike Montgomery provide the Mariners with four starts of varying degrees of success. Because the quality of his breaking balls are far behind his changeup, he has a sizable reverse platoon split this year—lefties are sporting a .399 wOBA against him while he’s holding righties to just .230. Considering the ballpark he calls home now, he should continue to have a successful run in the majors before Iwakuma or Paxton return. He may not have a place in the rotation once they return but he’ll continue to serve as a valuable piece of depth in case of emergency.

Tonight, he faces the team that drafted him and subsequently traded him. The Royals have three potent lefties in their lineup and Montgomery’s success tonight will be determined by the way he deals with the trio of Moustakas, Hosmer, and Gordon.