While it’s been a great year for top prospects getting called up to make their Major League debuts, it’s been very hitter-heavy. That’s not surprising, given that seven of the top 10 prospects right now are of the offensive variety.

So it’s a nice change of pace to have an elite-level pitcher get a chance to show what he can do. At No. 21 on the Top 100, Mitch Keller will become the highest-ranked pitching prospect to debut this season when he starts the second game of the Pirates’ doubleheader in Cincinnati on Monday.

The 23-year-old has made a slow and steady climb to this point since being the Pirates’ second-round pick in the 2014 Draft. He’s hit some bumps along the way, most notably when he first got to Triple-A in 2018. Smart on the mound, the Pirates' No. 1 prospect has been able to make adjustments and finished last season strongly. He’s largely carried that over to this season (5-0, 3.45 ERA, 56 K/20 BB in 47 IP), though has been more effective of late, with a 3.27 ERA, .235 BAA, 24/6 K/BB in 22 innings this May as he’s gotten better at attacking upper level hitters. His career line (3.06 ERA, .228 BAA, 1.16 WHIP, 1.26 GO/AO, 9.3 K/9, 2.9 BB/9) speaks for itself.

Here’s what Keller will bring to his start against the Reds on Monday:

Fastball: During Keller’s struggles last year, he saw his velocity dip, but it’s come back since. Outside of that one stretch he’s consistently been able to touch 97-98 mph with his fastball and sit 93-96 with good sink. If you saw the Futures Game, you saw the velocity, as he hit 99 in his one inning of work. He misses bats and gets weak contact on the ground as well with the pitch.

Curveball: An excellent 11-to-5 breaker, this is Keller’s other strikeout pitch. It’s a true downer breaking ball with a lot of bite. Look for him to lean on this pitch, which flashes plus often, to attack big league hitters.

Slider: This is a new pitch for Keller that he’s added to his repertoire this year. It’s a cutter-like pitch and it’s been an effective weapon for him, giving advanced hitters a different look. It might be a Major League average offering at this point.

Changeup: He’s worked on his changeup quite a bit over the years to get it up to Major League average. It does have some fade and sink to it, eliciting some ground-ball outs, but it might be his fourth pitch at this point.

Control: This was a plus part of his game until recently. His walk rate jumped in 2018 up to 3.5 BB/9 and he’s walked 3.8 per nine so far this year. Still, his career mark is 2.9, and he’s looked more like his old self in his four May starts, walking just 2.45 per nine during that stretch. When he repeats his delivery well, he is a strike-thrower, one who eventually could have above-average overall command.