During a less than exciting 2017 season, one of the more positive developments for the Royals organization was the success of Scott Alexander in the major league bullpen. After a few years of being a good reliever in the upper-minors, Alexander took his sinker took to the next level and rode it to a 2.48 ERA, 3.23 FIP, and absurdly high 73.8% GB-rate. Months following the conclusion of his career-year, he was flipped to the Dodgers in a rather questionable trade, leaving a hole in the Royals bullpen.
Weeks before that trade, the Royals had acquired a right-handed pitcher by the name of Brad Keller, hailing from the Diamondbacks organization, in a Rule 5 transaction. The 22-year-old figured to have a good, not great shot of making the major league club heading into Spring Training, but a good stint down in Surprise (10 IP, 9 H, 3 ER, 4 BB, 14 SO) locked himself a spot on the Opening Day roster.
The expectations for Keller this season weren’t particularly high, as the same is for most pitchers making the jump from AA to the majors. It’s early, but Keller so far has looked like one of the more impressive pitchers on this underwhelming Royals staff. The peripherals aren’t eye-popping for a 6.2 inning stint (2.70 ERA, 2.81 FIP, 5.4 K/9, 2.7 BB/9), but that isn’t what I wanted to specifically highlight here. What I wanted to point out was an interesting comparison I had thought up between the aforementioned relievers, Alexander and Keller.
Keller hasn’t exactly had the most exciting career as a prospect. An eighth round pick in the 2013 draft, he had some up and down seasons in the lower-minors, mostly as a starter, before turning in a career-year in his first taste of Low-A in 2015, putting up a 2.60 ERA and 3.13 FIP in 142 IP. He followed this up with two adequate seasons at High-A and AA in the 2016 and 2017 seasons.
Though the right-hander has turned in good numbers for the most part throughout his minor league career, but the bland profile as a starter is what kept him from climbing high onto the prospect radar, being ranked as the #30 prospect in a lowly Royals system this past offseason
The key to Keller’s success is locating his low-90s sinker, which he didn’t do as consistently in 2017. When he’s on, he pounds the bottom of the strike zone, spots his fastball on both sides of the plate and generates a lot of groundouts. He’ll also mix in an average slider and changeup.
Keller’s walk rate jumped from 1.7 per nine innings in 2016 to 3.9 last year, and Double-A hitters took advantage of him when he fell behind in the count. He has a strong build and has stayed healthy throughout his pro career. If he can command his sinker like he has in the past, he could find success as a back-of-the-rotation starter.
What Keller has always drawn praise on is his sinker and its ability to induce ground-ball outs, as mentioned above. As is obviously the case with Scott Alexander. In his past three minor league seasons, he’s posted GB-rates of 55.6%, 55.1%, and 49.6%, ranking 7th, 2nd, and 7th among qualified pitchers in his respective league.
FB% leaders among qualified relievers
Like many groundball artists, one common thing found is a prominent reliance on a sinking fastball. Now Alexander is probably more of an outlier with his sinker usage (he’s thrown his sinker a whopping 84.2% of the time to lead the majors), but Keller still throws at a high rate (26.7% usage rate ranks in the top third of the major leagues). The results on the sinker can be found to be very similar in batted ball results also.
Outside the sinker, the repertoires look similar too. As a starter, Keller mainly worked as a fastball, slider, changeup pitcher, exactly like Alexander’s current collection of pitches. But working out of the bullpen early in the year, Keller has ditched the changeup, using a sinker/slider combo that he’s comfortable with as a reliever. The biggest difference between the two is probably velocity, with Keller usually sitting around 94-95 MPH in the bullpen and Alexander working at around 92-93 MPH.
With the early success of Keller combined with the disappointing performances of some arms in the bullpen, it looks extremely likely that Keller will spend the whole season on the major league roster and remain in the organization. If possible, my preference would be to keep him working as a reliever. The added velocity in the bullpen to go along with his downward fastball has intrigued me. And with the bullpen being as depleted as it is, don’t be surprised if he’s playing a major role on this team come sooner or later in the season.