Which Diamondback has the most batters-faced/plate-appearances in their career? Merrill Kelly pitched to 8594 batters so far, per Baseball Reference. And I’m not sure whether that included the 91 batters he faced in the postseason. It included 2234 batters in the minors, 3212 batters “foreign”, and 3085 batters in the Majors (plus “other”).
On the position player side, Ketel Marte’s 6375 plate appearances were the most. It included 2289 batters in the minors, 133 batters “foreign”, and 3953 batters in the Majors.
When a batter faces the starting pitcher more than once in the same game, each time he steps to the plate is a plate appearance. Let’s look at the first, second, and third plate appearances. We will ignore plate appearances after the third. We will ignore plate appearances after a reliever enters the game.
Let’s focus on seven pitchers who could begin the season as regular starters (instead of spot starters or emergency starters) for the Diamondbacks next season.
Regular season. The first time through the order as starters, their ERA’s ranged from 0.96 to 5.13. Five pitchers had great ERAs the first time through the order:
- 0.96 ERA, Slade Cecconi (small sample size)
- 2.76 ERA, Merrill Kelly
- 3.03 ERA, Eduardo Rodriguez
- 3.14 ERA, Zac Gallen
- 4.30 ERA, Brandon Pfaadt
And Ryne Nelson and Tommy Henry had good ERAs (5.13 and 5.29).
Let’s look beyond the first time through the order. The following table shows the first three plate appearances for the regular season. The pitchers were divided into three groups: starters who started in the postseason, starters who were relievers in the postseason, and starters who did not pitch in the postseason.
The newly acquired Eduardo Rodriguez stands alone as the only starter whose ERA was great in each of the times through the order. That may be his consistency superpower. Here are more reasons to be optimistic about him.
Zac Gallen, (who pitched better in home games) and Merrill Kelly (who will defy the aging curve), whom were overall the most consistent starters (quality starts, streaks of games with less than 5 earned runs, seasons with 150 innings pitched, and game score consistency) were great until the third plate appearance, when their ERA fell to merely good. Nevertheless, these two starters are strong pillars of the rotation.
Next season, it’s widely thought that Brandon Pfaadt will pitch in the fourth spot in the rotation. However, that prediction is largely based on how well he pitched in the postseason (we will consider the postseason next). In the postseason he almost never went beyond the first two times through the order. Whether he can pitch the third time through the order is an important question, without a clear answer.
Though the reasons are unknown to me, it is very promising that Tommy Henry’s (Better than Bumgarner) ERA in his second/third plate appearances shined brightly compared to when he faced batters for the first time. He is perhaps the leading candidate for the fifth spot in the rotation.
Ryne Nelson (who dramatically pitched much better in away games) will be contending for the fifth spot in the rotation. Whether he should be a starter or a reliever is an important question. Last season as a starter, his strikeouts-per-batter-faced was 15.2%. As a reliever, his strikeouts-per-batter-faced was 25.0% (regular season), and 23.3% (postseason).
Slade Cecconi pitched very few innings as a starter. Perhaps his lack of experience in the Majors indicates he is not yet ready to be an everyday starter.
Postseason. Zac Gallen was a Cy Young contender. He is a great pitcher. Having said that, his ERA in the postseason was at best average (except for the second time he faced each batter). Perhaps batters made an adjustment in the postseason. In any case, I’m confident Zac Gallen will bounce back to pitch much better next postseason.
In the postseason Merrill Kelly’s ERA was better than the regular season for each of the first, second, and third plate appearances. His ERA was near an awesome 2 the first two times through the order. The third time through the order his 3.38 ERA was great, although not quite as awesome. Next season, my prediction is that he will defy the aging curve and pitch just as well.
In the postseason, Brandon Pfaadt pitched like he belongs in the rotation next season. Most impressive was his 29.9% strikeouts-per-batter-faced in the postseason. A possible concern is that it appears that the Diamondbacks intentionally pulled him before facing batters for the third time.
“His starts in Game 3 and Game 7 of the NLCS featured the two highest swing-and-miss totals of his young career despite the fact that he threw just 70 and 64 pitches, respectively.” — Chris Gilligan
The following table shows the postseason starters.
In the postseason, Slade Cecconi and Ryne Nelson pitched in relief. Cecconi’s ERA was 0 in 2 innings pitched. Nelson’s ERA was 5.68 in 6.1 innings pitched.
The following table shows SLG and OBP for first, second, and third plate appearances in the regular season for all Diamondbacks batters (plus newly acquired Eugenio Suarez) with at least 250 total plate appearances. They are shown in order of their regular season SLG, from best to worst. A green stat means they were above the average in the Majors. A purple name means their third plate appearance SLG was better than their first plate appearance SLG.
Last season, average SLG in the Majors was .414. Two players with above average SLG for the season Christian Walker and Ketel Marte, had better SLG in their third plate appearances than their first plate appearances. Their consistency was remarkable.
Last season, Corbin Carroll’s .506 SLG for the season was the highest of the Diamondbacks. Next season, he could improve his SLG if he improves his performance in his third plate appearances.
Gabriel Moreno came the closest to being consistently above average in SLG and OBP, although his season average SLG was slightly below average in the Majors (.408 vs .414).
Although newly acquired Eugenio Suarez SLG was below average, next season his SLG will likely improve to close to his .459 SLG from 2022. It’s not a sure thing because ZiPS’ projected 80th percentile SLG is .450 (meaning the odds are he will fall short of a .450 SLG). Two reasons to expect an increased SLG are:
- His 90.3 MPH average exit velocity was the third highest of the batters in the table (and above-average in the Majors).
- His SLG was higher (than this season’s SLG) in each of his career season except his rookie season (2014).
Five of the six batters with below average SLG for the season had SLG and OBP that varied a lot between first, second, and third plate appearances. My optimistic view is that variance is an indication that improvement is possible.
Noteworthy was that Emmanuel Rivera and Jake McCarthy had above-average SLG in their third plate appearances despite their below-average season SLG. Their third plate appearances show successful adjustments during the game.
Points about the Diamondbacks’ pitchers follow:
- The newly acquired Eduardo Rodriguez stands alone as the only starter whose ERA was great in each of the times through the order.
- In the regular season, Zac Gallen and Merrill Kelly were great until the third plate appearance, when their ERA fell to merely good. In the postseason Merrill Kelly’s ERA was better than the regular season for each of the first, second, and third plate appearances.
- In the postseason, Brandon Pfaadt’s 29.9% strikeouts-per-batter-faced was impressive. Whether Pfaadt can pitch the third time through the order is an important question without a clear answer.
- Next season, Ryne Nelson will be contending for the fifth spot in the rotation. Whether he should be a starter or a reliever is an important question. His strikeout rate was better as a reliever.
- Slade Cecconi’s lack of experience in the Majors indicates he may not yet ready to be an everyday starter.
Points about the Diamondbacks’ batters follow:
- Four Diamondbacks’ batters had season average SLG above the average in the Majors. Two of those four players, Christian Walker and Ketel Marte, had better SLG in their third plate appearances than their first plate appearances. Their consistency was remarkable.
- Five Diamondbacks’ batters has season average SLG below average for the Majors. Their SLG and OBP varied a lot between first, second, and third plate appearances. My optimistic view is that variance is an indication that improvement is possible.
- Eugenio Suarez’s SLG was below average, but next season his SLG will likely improve to close to his .459 SLG from 2022.