Reviewing the Rookie Pitchers — Through Jul 18, 2023

I last reviewed rookie starting pitchers just over a month ago. Naturally, there have been a host of new faces that have ascended to the Majors since. So let’s get back to reviewing some of the more recently recalled rookies starting pitchers.

Bryan Woo | SEA

The fourth ranked Mariners prospect, Woo’s scouting grades feature an above average fastball, and not much else. And yet, he posted strikeout rates over 30% at every minor league stop, with double digit SwStk% marks. That was apparently enough for the Mariners to deem him ready for the Majors, as he was promoted after having never thrown a pitch at Triple-A. So far in eight MLB starts, his strikeout ability has mostly carried over, with his strikeout rate sitting at 28.8% and a SwStk% nearly identical to his Double-A mark.

He’s done that despite throwing either his four-seamer or sinker about 76% of the time, leaving little room for the usage of his secondary pitches. You don’t typically see a high strikeout rate with such heavy four-seam/sinker usage! But Woo’s four-seamer has been elite, generating a 14.6% SwStk%, so the scouting grade was right on about that being his best pitch. That said, it’s really tough to maintain such a high SwStk% on a four-seam fastball. His slider has been pretty good too at a 16% SwStk%, while his cutter has been fine as well at 12%. So all his non-four-seamers have done a slightly better than average job at generating whiffs, while the four-seamer has been the standout.

His velocity sits at 95.2 MPH, peaking at 97.6 MPH, so you would certainly thing he could eventually parlay the big fastball into more effective secondaries. For now though, I would worry he won’t be able to maintain the whiff rate on his four-seamer and his strikeout rate could suffer.

He has also been an extreme fly ball pitcher throughout his short professional career and he had induced a high rate of pop-ups in the minors. The pop-ups haven’t translated to the Majors yet, and although his batted ball profile should result in a low BABIP, that hasn’t happened in the Majors either. A super low 64% LOB% is driving an ERA well above his SIERA and what’s even more interesting is a 2.78 xERA that suggests his BABIP should also be significantly lower, thanks to the low LD% and high FB%.

He’s got an interesting profile that is hard for me to forecast, but he’s certainly better than a 4.74 ERA. I think that makes him a nice trade target in deeper leagues and especially keeper formats.

Andrew Abbott | CIN

Abott was ranked fifth among Reds prospects and 99th overall, but with even worse scouting grades than Woo. His curveball rated as his best pitch with a 55/60 grade, but nothing else was particularly good, including his command. And yet, I couldn’t ignore his big minor league strikeout rates, including a 34.8% mark at Triple-A this year, backed by a 14.5% SwStk%. Oh, and he also struck out an absurd 36 of 56 batters faced at Double-A this year for a…wait for it…64.3% strikeout rate and 22.4% SwStk%! Scouting grades be damned, I care about actual results and this is someone I wanted to roll the dice with in my 12-team mixed league.

So far, his results have been fantastic, though much of it is aided by luck. He has overperformed his SIERA by nearly two runs, and xERA by more than a full run, thanks to a tiny .214 BABIP and astronomical 95.1% LOB%. Bottom line: his ERA is headed upward.

However, his full season line doesn’t tell the full story. It has actually been a tale of two different periods for Abbott. Over his first three starts, he generated just a 6.5% SwStk%, 16.9% strikeout, 12.7% walk rate, and 5.85 SIERA. Over his five starts since, he has been a completely different pitcher, and one more representative of how he performed in the minors. He has posted an elite 14.6% SwStk%, 33.6% strikeout, 6% walk rate, and 3.61 SIERA, which is only that high because of his crazy high 69.6% FB% (which is great for BABIP, but could result in lots of homers).

I think it’s fair to have allowed him a couple of starts to settle into the Majors before getting his groove on, so this latest five start stretch looks closer to Abbott’s current talent than his first three starts, even if he does regress some. He has also made some pitch mix changes, throwing his four-seamer less and changeup and slider more. All of his secondaries have generated a double digit SwStk%, with his changeup coming in highest, followed by his slider. I would imagine these marks are even higher during his five game stretch than these full season rates, which are already solid enough.

Clearly, the risk here is all the fly balls, especially in a home ballpark that inflates home runs. It’s really not a very good combination. But given his strikeout ability and recent control improvement, the HR/9 might not be too scary, as limiting contact and allowing more solo shots will keep his ERA from skyrocketing.

Gavin Williams | CLE

Williams was the fifth ranked Guardians prospect and 76th ranked overall. After posting impressive strikeout rate and SwStk% marks in the minors, he has made five starts so far in the Majors and has only mustered a 19.2% strikeout rate and 10.8% SwStk%. It’s not terrible, but a far cry from what we expected given his recent minor league history.

Williams throws hard, averaging 95.9 MPH with his four-seamer, and mostly mixes in a slider and curveball, with a lesser used changeup. His slider has been solid enough, but nothing special, at inducing whiffs, while his four-seamer has been good, just getting into a double digit SwStk%. On the other hand, both his curveball and changeup sit with single digit SwStk%, so those simply haven’t generated swings and misses.

As mentioned in Woo’s blurb, perhaps William’s high octane fastball velocity will eventually lead to a more effective curveball and changeup. Given the important of the fastball, it’s probably better to start with a strong fastball in the hopes of improving the secondaries, rather than the other way around.

Without a real ground ball or fly ball tilt, he doesn’t have any sort of benefit on his BABIP or HR/9 rates, but he does appear to be a slight fly ball pitcher, which could help his BABIP. Keep in mind though that his current .247 mark is likely highly unsustainable, even though it matches his small sample Triple-A mark this year.

Emmet Sheehan | LAD

The Dodgers’ 18th ranked prospect, he was actually slapped with 60+ grades on two pitches, which is something none of the pitchers above have been. And yet, he’s the worst ranked prospect! Also interesting is an ETA of 2025 and yet he has already made it to the Majors, a season and a half early!

Of course, Sheehan accomplished that by skipping Triple-A, thanks to an absolutely dominant Double-A stint this year. He recorded 53.1 innings and struck out 41.7% of opposing batters, with a 19.7% SwStk%. That isn’t quite at incredible as Abbott’s Double-A performance, but this one comes over a larger sample. Sheehan doesn’t have an extensive minor league track record, but wherever he has pitched, he has recorded an impressive strikeout rate and high SwStk% mark. That gets me excited.

What dampers my enthusiasm is a consistently high walk rate that has stood in double digit nearly his entire pro career, in addition to a high fly ball rate. That’s potentially lots of multi-run homers!

He also hasn’t translated his minor league strikeout rate to the Majors yet, as he has struck out just 17.1% of opposing batters. That just doesn’t cut it, especially when paired with a 10.5% walk rate. It’s very possible he’s simply not ready after skipping Triple-A, but like we saw above with Abbott, we should be patient with rookies as they adjust to the best competition in the world.