Arizona Diamondbacks’ 2022 report cards: Starting pitchers

Oct 7, 2022, 7:09 PM | Updated: 8:02 pm

Zac Gallen #23 of the Arizona Diamondbacks pitches in the first inning against the Milwaukee Brewer...

Zac Gallen #23 of the Arizona Diamondbacks pitches in the first inning against the Milwaukee Brewers at Chase Field on September 04, 2022 in Phoenix, Arizona. (Photo by Norm Hall/Getty Images)

(Photo by Norm Hall/Getty Images)

For many reasons, the Arizona Diamondbacks should be proud of their 2022 season.

For starters, they improved their win total by 22. They also had their highest winning percentage since 2019.

The route the D-backs took to achieve their 74-88 season was unique. They were a middle-of-the-pack offense and tied the league lead in bullpen losses.

However, they had one of the best one-two punches in the league out of their rotation, and that duo accounted for nearly one-third of the team’s wins.

On the topic of the starting rotation, this position group is the first to receive its report card for 2022.

Let’s take a look at some key factors in choosing their grade.


With a 4.05 ERA, the D-backs rotation finished the regular season 19th in the majors. However, excluding the 34 games started by left-handers Madison Bumgarner and Dallas Keuchel, they had a 3.71 rotation ERA in 128 games — ninth in baseball.

That said, their rotation as a whole was 22nd in strikeouts per nine innings (K/9) and called strike plus whiff rate (CSW%). There were several metrics they ranked, at best, in the middle of the pack among MLB teams.

Despite that, the rotation improved its ERA by 1.15 runs from 2021. Not only that, but the aforementioned one-two punch of right-handers Zac Gallen and Merrill Kelly both improved dramatically.


In 2021, injuries limited Gallen to just 23 starts and 121.1 innings. While he struck out a team-best 10.3 batters per nine innings, his 4.30 ERA was fourth among D-backs starters with at least five starts.

This season, Gallen’s K/9 dipped, but his ERA improved from 4.30 to the fourth-best mark in the National League at 2.54.

Among D-backs pitchers to make multiple starts, he led in FanGraphs’ WAR (fWAR), HR/9, K/9 and BB/9, among other statistics.

Gallen also won NL Pitcher of the Month in August and set the franchise record with 44.1 consecutive scoreless innings.

He likely won’t win the Cy Young Award for the NL, but his breakout gives the Diamondbacks a legitimate ace to build their rotation around. That reality holds more weight than where the staff ranked statistically.


This was easily the best season of Kelly’s four-year MLB career, especially considering his 2020 only had five starts.

In a career-high 33 starts in 2022, he posted career-bests in innings pitched, ERA, expected ERA, strikeout rate and fWAR.

Moreover, he ranked second among D-backs pitchers in fWAR and ERA, behind only Gallen.

Kelly also took home NL Pitcher of the Month honors for July. After Gallen won the award in August, the two became the first D-backs starting pitching duo to win consecutive awards since Curt Schilling and Randy Johnson in 2002.

Kelly’s emergence as a very good No. 2 starter, especially in tandem with Gallen, is big for the Diamondbacks moving forward.

The rookies

It wasn’t just Gallen and Kelly making noise in the rotation this season. Though only a seven-start sample size, right-handers Drey Jameson and Ryne Nelson each pitched to sub-1.50 ERAs in 42.2 innings.

The two of them combined for a 1.48 ERA, a .191 opponent batting average, had 8.4 K/9 and stranded 93.6% of baserunners.

Their 0.8 fWAR combined for sole possession of third place in the D-backs rotation behind only Gallen and Kelly. Jameson accounted for 0.5 fWAR and allowed four earned runs in 24.1 innings.

The two of them contributing at the MLB level could make things interesting in shaping up the rotation behind the one-two punch.

Zach Davies has a mutual option for 2023 and the D-backs’ top pitching prospect, Brandon Pfaadt, has yet to debut. With Gallen, Kelly and Bumgarner as likely rotation locks next season, that leaves four options for two spots.

Jameson and Nelson emerging as viable options may not guarantee them Opening Day spots, but will provide the team with more pitching depth than they entered 2022 with.


The D-backs’ highest-paid player, taking up 17% of the payroll, Bumgarner had an even bigger disappointing season.

In 30 starts, the former San Francisco Giants World Series champion posted a 4.88 ERA, struck out a career-worst 6.4 per nine and allowed hard contact (95-plus mph exit velocity) at his highest rate of the Statcast era (since 2015) at 42.8%.

With how Gallen and Kelly pitched, Bumgarner didn’t have to be the best arm in the rotation to be worth his $18 million salary. However, the way his season unfolded — having a start skipped multiple times — is a major disappointment to the Diamondbacks’ season.

Among starters with at least 150 innings pitched, the southpaw had the seventh-highest ERA, tied for the second-most losses and the fourth-fewest strikeouts per nine innings.

Arizona still owes Bumgarner $32 million in adjusted salary in the next two seasons. He has a 4.98 ERA in his first 65 starts as a Diamondback.

Final grade: B

Rebounding from a 52-win 2021 season, the rotation’s grade is based more on what this season meant for the future than the actual numbers overall.

While Bumgarner detracted from the rotation a lot, especially as the highest-paid member of the team, the rest of the rotation pitched very well.

As previously mentioned, the rotation ERA without Bumgarner and Keuchel was 3.71, which would’ve been good for ninth in baseball.

The breakout of Gallen as an ace, and Kelly as a viable No. 2, was significant. Not to mention the success in a seven-start sample size from Jameson and Nelson.

In general, there was a lot more good-to-great in the Diamondbacks rotation than their overall numbers suggest. While Bumgarner’s struggles bogged down the overall numbers, Gallen, Kelly, Jameson and Nelson combined for a 2.82 ERA with 409 strikeouts in 427 innings pitched.

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