No strangers to developing high school pitching talent, the Pirates knew it would take time for Keller, who was given an over-slot bonus as a second-round pick in 2014 to get signed away from his North Carolina commitment, to develop. Though he missed time early in his career because of injuries, he's moved steadily up the ladder since, starring in the Arizona Fall League in 2017 and starting the 2018 Futures Game. He narrowly missed pitching enough innings in his big league debut to graduate off prospects lists, and while he struggled for much of his time in Pittsburgh, he did end the season on a strong note.
Even when he was struggling, Keller's pure stuff was plenty good enough. His fastball topped out at 98 mph and averaged just over 95 mph. He'll throw it with good heavy sink to get ground-ball outs and he'll also miss bats with it. His 11-to-5 power curve is another out pitch for him, but he actually threw his newer slider more once he was in the big leagues and it became a good weapon for him, especially at the end of the 2019 season. He will need to throw his changeup more as he establishes himself, but it's an average off-speed pitch.
Keller has struggled with his command over the last couple of seasons, both in terms getting too much of the strike zone and an increased walk rate, though that was a bit better in 2019 overall. At the end of the year, the quality of strikes was much better, as was his overall execution of his pitches, something the Pirates are confident will carry over to 2020.
Scouting grades: Fastball: 65 | Curveball: 55 | Changeup: 50 | Control: 50 | Overall: 55
Hailing from the Iowa high school ranks, Keller was a projectable right-hander who jumped onto the radar in 2014 thanks to a velocity spike. The Pirates saw enough to give him seven figures to walk away from his commitment to the University of North Carolina. Injuries hampered him early in his pro career, but he still made it to Triple-A at age 22 and started the All-Star Futures Game in 2018, earning a spot on the 40-man roster in the offseason.
The velocity jump that Keller showed in his senior year of high school has largely stayed with him. He touched 99 mph in his one-inning Futures Game start and often touches 97-98 mph, while sitting in the 93-96 mph range. Thrown with excellent sink, Keller gets a lot of groundball outs, but also elicits swings and misses with both his fastball and his plus 11-to-5 downer curveball. He's worked hard to improve his changeup, and while it's still not as good as his two plus offerings, it gives him a third Major League average offering.
While Keller's walk rate went up in 2018, some of that came with him trying to do too much when he first got to Triple-A, a stretch where his velocity dipped and he lost some feel for his stuff and delivery. He bounced back to finish strongly, with signs pointing in the right direction as a potential frontline starter with plus stuff and command.
Scouting grades: Fastball: 65 | Curveball: 55 | Changeup: 50 | Control: 60 | Overall: 60
A jump in velocity heading into his senior year in high school put Keller more firmly on the Draft prospect map in 2014 and landed him in the second round, where the Pirates went above pick value to sign the Iowa prepster away from his North Carolina commitment. His pro career started slowly, as he missed most of 2015 with a forearm strain, but while he missed some of 2017 with a back issue, he still reached Double-A at age 21, dominated in the playoffs there and then capped things off as one of the best pitching prospects in the Arizona Fall League.
Keller has an exciting combination of stuff plus command. He can sit in the 93-96 mph range and touch 97-98 mph without much effort with his fastball and commands it extremely well. He'll throw it with excellent life down in the zone, both missing bats and inducing weak ground-ball contact. His 11-to-5 curve flashes plus as well. His changeup has long been his third pitch, but it's improved and he showed a solid one while working on it during his AFL stint. He throws all of his pitches for strikes, continues to refine his ability to game plan and does an outstanding job of staying away from walks and home runs.
Keller just needs a little more development time at the upper levels of the system to sharpen his secondary pitches in order to be ready to impact a big league rotation. At worst, he looks like a solid No. 3, but he has the chance to be more than that in the future.
Scouting grades: Fastball: 65 | Curveball: 55 | Changeup: 50 | Control: 60 | Overall: 55
Having developed several pitchers drafted as high schoolers, the Pirates know that patience is of the utmost importance. So there was no panic when Keller, who was given an over-pick value deal to sign in 2014 instead of head to North Carolina, started his career slowly. He didn't pitch much in 2015 because of injuries, most notably a forearm strain, but he made a huge leap forward during a healthy 2016, finishing the year with some stellar playoff starts and helping Bradenton win the Florida State League title.
Keller's fastball keeps on getting better, now sitting in the low-to-mid-90s, with the ability to reach back for more. There's a ton of sink to it and that, along with his improved changeup, elicits ground-ball outs. His 11-to-5 curve is his best secondary pitch, and he misses plenty of bats with that and his heater. Mature beyond his years, Keller has vastly improved his ability to harness his stuff and fill the strike zone with all of his pitches.
Keller had to deal with another injury, this time a back strain, in 2017, but is still very much poised to join the group of elite-level pitching prospects in the game. Still very much projectable, he now looks like he could be a frontline starter if he reaches his ceiling.
Scouting grades: Fastball: 60 | Curveball: 55 | Changeup: 50 | Control: 50 | Overall: 55
The Pirates loved Keller coming out of the Iowa high school ranks in the 2014 Draft, watching his velocity spike and then going over-pick value to sign the right-hander away from his North Carolina commitment. Injuries -- most notably a forearm strain that kept him off the mound for much of the 2015 season -- kept Keller from truly showing what he can do until 2016 when he was one of the best pitching prospects in the South Atlantic League.
The younger brother of Orioles pitching prospect Jon Keller, Mitch is tall and projectable, with a fastball that now sits in the 90-94 mph range. When he's not trying to overthrow, he has good sink on it, with the potential to be a ground-ball machine. He can really spin his breaking ball, an 11-to-5 curve that could be above-average in the future. He's shown some feel for a changeup, and his third pitch was developing well as he got more consistent mound time.
Keller did get back on the mound at the end of the summer, then made good progress during instructs, particularly on the not trying to light up the radar-gun front. If he can put the injuries behind him, he has the chance to be a physical right-hander with a three-pitch mix, a recipe for a mid-rotation starter.
Scouting grades: Fastball: 60 | Curveball: 55 | Changeup: 45 | Control: 45 | Overall: 45
The Pirates went over pick value on more than one occasion to go after high school pitching talent in the 2014 Draft. Keller got $1 million to forego his commitment to the University of North Carolina. His progress was slowed by a forearm strain that kept him off the mound for much of the rookie-level year.
Keller's velocity spiked as a senior in the Iowa high school ranks, raising his stock considerably. The younger brother of Orioles farmhand Jon Keller, Mitch now sports a fastball that sits comfortably in the 90-94 mph range. Tall and projectable, there might be more to come fastball-wise. He's shown good sink and the ability to get groundball outs. Keller also throws an 11-to-5 curve, which has gotten tighter, though it still needs refinement. He has some feel for a changeup, but it's behind the other two pitches.
There is work to be done on Keller's mechanics and his command. The Pirates are no strangers to drafting and developing high school arms, so they know all about being patient. The end result could be a starting pitching groundball machine.
Scouting grades: Fastball: 60 | Curveball: 55 | Changeup: 45 | Control: 45 | Overall: 50
Saving money with their first two picks in the 2014 Draft enabled the Pirates to go slightly over pick value to sign Keller, the top prospect from the state of Iowa, away from his college commitment to North Carolina.
Keller, whose older brother Jon pitches in the Orioles' system, took a huge leap during his senior year to move up Draft boards in a hurry. A spike in velocity had the right-hander throwing 90-94 mph, thanks to getting in much better shape. Keller's 11-to-5 curveball has gotten harder and tighter as well, giving him a second potential above-average pitch. He hasn't needed it much, but he shows some aptitude for a changeup, as well.
Keller is still learning to harness his stuff, but the Bucs have shown a willingness to patiently develop young, projectable arms in the past, something they'll have to do to help Keller reach his potential.</p>