This is a lot harder than assessing hitters’ development. At least in my opinion, stats, especially traditional ones like ERA, have limited value in projecting pitching prospects. There’s also a small sample size problem, because a couple bad outings can mess up a half season’s stats pretty easily. I’m going to go team-by-team here.
A lot of the Indians’ pitchers have had pretty much the season you might have predicted. Edgar Santana and Dovydas Neverauskas have shown the excellent stuff we knew they had. Clay Holmes and Tyler Eppler got off to good starts, but more recently their performances have been uneven, much as they were last year in AA. Drew Hutchison has looked like what he probably is: a solid AAA pitcher.
One definite disappointment has been Nick Kingham. After returning from a minor injury in May, he had several good starts, but since the beginning of June he has a 1.60 WHIP. One positive sign is that he’s striking out almost exactly one per inning. The biggest concern here, though, is that Kingham will have no options left after this year. He doesn’t look nearly ready to take a spot in the major league rotation, but unless they move him to the bullpen — which I seriously doubt they’ll consider — the Pirates are going to be left in a very difficult situation at the end of March next year.
The two pitchers at Indy who matter the most to the major league team this year, Steven Brault and Tyler Glasnow, are doing well now. Brault struggled early with the same problem he had in the majors last year: getting behind in counts, leading to high pitch counts, sometimes too many walks, and early departures. In April, Brault had a 1.44 WHIP and 3.86 ERA, and averaged five innings per start. Since then, he has a 0.99 WHIP and 1.31 ERA, and has averaged over six innings per start, 6.5 since June 1. He’s striking out 8.4 per nine innings.
The encouraging development with Glasnow is that his velocity has increased since he went back to AAA. In the majors, he seemed to have lost the ability to dominate hitters, which he did consistently in the minors. His fastball averaged 94 mph with the Pirates. At Indy, he’s been sitting in the upper-90s and has hit 100 at least a handful of times. He’s struck out 49 in 29.1 IP and opponents have batted .168 against him, barely half of what major leaguers battered him for. This suggests that he was holding back in the majors, probably to help with his control. Neal Huntington has said the Pirates believe Glasnow is better when he airs it out. If his confidence was an issue in the majors, there are reasons to think/hope he might be getting it restored in AAA.
There are two pitchers with the Curve whose seasons have unequivocally been a step backward. One is Yeudy Garcia, who currently sports a 1.84 WHIP and 6.39 ERA. (When they’re that bad, traditional stats work just fine.) Garcia’s been plagued by command issues, walks and high pitch counts. His shoulder, which bothered him last year, apparently is fine now, but he hasn’t recovered the upper-90s velocity he showed in 2015. He’s generally in the low-90s now. Garcia recently returned to Altoona from a lower back problem and the Pirates now have him pitching out of the bullpen. The second problematic season belongs to Brandon Waddell, who’s missed time in two stretches due to a forearm strain. He’s made only eight starts, with a 4.55 ERA. His WHIP (1.27) isn’t bad, though, and he’s striking out a batter an inning.
Several relievers at Altoona are having very good seasons, although none of them has the kind of stuff you usually associate with relief prospects. Miguel Rosario throws often just in the mid-80s, but he throws from roughly a high-sidearm slot and seems to be hard to square up against. His ERA (0.89) is great, but his WHIP (1.40) much less so due to control issues and he’s a flyball pitcher. Tate Scioneaux has a good ERA (2.01) and great WHIP (0.93), but he doesn’t throw hard and is an extreme flyball pitcher. The reliever with the best chance of moving forward may be Sean Keselica, who’s pitching very well at Altoona after throwing just one inning at Bradenton. Keselica’s advantages are that he has solid velocity for a lefty, he’s a groundball pitcher, and he’s been death to left-handed hitters this year, holding them to an .083 average.
The Marauders have had probably the most interesting pitching staff in the system. It’s headed, of course, by Mitch Keller. He’s missed some time with back trouble and hasn’t dominated every single time out, but the numbers are still very good and the stuff is still there.
Two Bradenton pitchers already earned promotions to Altoona. Dario Agrazal has seen his velocity increase over the last couple years, to the point where he’s sitting at 94-95. He’s struggled in the past, though, due to lacking an out pitch and being very hittable. Opponents hit .294 against him last year, but this year at Bradenton they hit .243 (although some of that no doubt is the pitchers league in the FSL). He walks very few, gets a lot of grounders and keeps the ball in the park, so he’s often able to pitch around the hits. He also increased his K/9 this year from 5.3 to 7.1 and he’s averaged over six innings per start, which is a lot for class A. He suffered a pectoral strain in his first start in AA, though, so he’s out right now.
The other promotion was Jake Brentz. His big step forward was apparent in spring training, when his fastball jumped from the mid- to the upper-90s, sometimes reaching triple digits, which is pretty exciting for a lefty. He’s retained that velocity in-season, but still has command issues to work out. He fanned well over a batter an inning for Bradenton, but he’s had a lot more trouble with the hitters in AA.
The biggest surprise on the Marauders’ staff has probably been Pedro Vasquez, acquired with Brentz for Arquimedes Caminero. Vasquez even started (and lost) the league’s all-star game. Vasquez doesn’t have dominant stuff, but he does throw 92-93, he’s still only 21, and he doesn’t walk many hitters. He currently has a 2.52 ERA and he’ll go over his previous high in innings during his next start.
I’m not sure I’d say that Taylor Hearn has taken a step forward or backward, as he’s shown the expected strengths and weaknesses. He’s dominated much of the time, as shown by the .206 opponents’ average and 10.5 K/9. His control, which has always been an issue, has largely been a manageable one, with a BB/9 of 4.0. The negative is that he’s been prone to bad innings, leading to a 4.35 ERA. Hearn is already well above his previous high for innings, so we’ll see whether the Pirates start reducing his workload at some point.
Gage Hinsz simply hasn’t had a good year, after a promising season last year. Command issues have led to a .291 opponents’ average and 1.48 WHIP. He also isn’t missing bats, with a 5.6 K/9. He has, however, pitched much better in his last several starts.
The Power has had one big surprise on the pitching staff, one disappointment, and one pitcher who’s a bit of both.
The surprise is lefty Oddy Nunez, who a year ago looked like a guy to use up some relief innings at the lower levels. This spring, Nunez’ velocity jumped to 93 mph and his breaking ball improved, and he ended up in the West Virginia rotation. His numbers have been good (1.05 WHIP, .205 BAA, 8.0 K/9) and he’s only 20. He’s done this well despite making the jump to full season ball from the GCL last year. The Pirates have been slowly building up his workload, recently getting it to five innings per start, as he threw only 34 innings last year.
The disappointment has been Blake Cederlind, who looked very good in spring training, including 97 mph velocity. He’s had a rough time and has been struggling more than ever recently. The numbers overall are just ugly, although he’s at least striking out almost a batter an inning.
The most talented pitcher at West Virginia, Luis Escobar, has also probably been the most erratic. He started the season piling up huge strikeout totals, but at some point the hitters apparently figured out that the pitches they were chasing were seldom in the strike zone. Escobar has struggled much of the time since April (when he fanned 45 in just 27.1 IP) with walks and high pitch counts. The talent is still apparent, though, as despite the struggles he’s held opponents to a .225 BA and he’s fanned 100 in 75.2 IP.