How Diamondbacks’ pitching rotation is shaping up with approaching trade deadline

The Arizona Diamondbacks enter the back half of July with plenty of questions about their starting rotation. Not all of them start with the trade deadline at the end of the month, but they end there.

Arizona’s got injuries and performance issues to worry about, as well as the feeling it is a starter short of potentially making noise in the postseason.

Arizona Sports editors Alex Weiner and Kellan Olson will reset the rotation with that in mind to assess the present and what’s next.

The Diamondbacks’ certified ace

Zac Gallen

When healthy, the top of the D-backs’ rotation is one of the NL’s strongest with Zac Gallen and Merrill Kelly, who are both top-10 in the league in ERA among qualified pitchers.

The D-backs are 13-8 in games Gallen starts, as he has been the team’s skid-stopper and a reliable force to go deep into games.

Within a rotation full of ups and downs this year, Gallen has gone at least six innings in 15 of 21 starts with a 3.18 ERA and 3.04 FIP.

His standing among the league’s best was on display as he started the All-Star Game and is in the thick of a Cy Young race.

Arizona has only three healthy starting pitchers on its active roster entering their weekend series against the Reds, but it’s always easier to figure out the rotation knowing the top is secure.

— Alex Weiner

Who’s on the shelf for the D-backs?

Merrill Kelly

Kelly is having a career year and has been the legitimate No. 2 to Gallen. His 3.22 ERA and 1.14 WHIP just about mirror his numbers from 33 outings in 2022, inspiring even more belief that Kelly is this guy now after his first three MLB seasons in the Valley.

A stint on the 15-day injured list has been Kelly’s fate since June 27 due to right calf inflammation via a blood clot. Kelly’s rehab stint is still ramping up and the righty will throw his second simulation game in the Arizona Complex League (ACL) on Thursday. Manager Torey Lovullo said Tuesday that Kelly could be back for the three-game home series against the St. Louis Cardinals that begins Monday.

Arizona has been able to hold a four-man rotation, but it will require a bullpen game in Cincinnati, which Lovullo called likely. The D-backs have a day off a week from Thursday on July 27 after the Cardinals series, so Kelly’s time up could come either shortly before or after that.

— Kellan Olson

Zach Davies

Davies was placed on the 15-day injured list with lower back inflammation on Wednesday and it might coincide with the end of his stay in the rotation. Davies’ ERA on the season now sits at 7.38 and jumped from an already concerning 5.79 when he got hurt earlier in 2023.

The right-hander’s go-to pitches are his sinker (34.9% of his total pitches) and his changeup (25.7%). Opposing hitters are batting .342 on the sinker and .299 off the changeup, per Baseball Savant. That’s brutal.

The hesitation in dropping Davies would be an over-reliance on young pitching. The D-backs had Tommy Henry, Ryne Nelson and Brandon Pfaadt all competing for one spot in the spring. Now all three sit in the current rotation. Perhaps the trade deadline could help ease that transition but it’s just about necessary at this point for Davies to move on.

— Kellan Olson

Who are the young pitchers the D-backs are counting on?

Ryne Nelson

The Nelson experience has been far from smooth but with some tremendous highs. He has three starts of seven innings and two or fewer runs allowed, including his latest in a 5-3 win over the Atlanta Braves on Wednesday.

He also has five outings in which he was chased before getting out of the fifth. The organization has stood behind the rookie all year, as he is the only young arm in the rotation who has not spent time in Triple-A in 2023.

His splits home and away, which can be overrated in some cases, are quite dramatic. Nelson has a 2.67 ERA on the road and 8.08 ERA at Chase Field.

Opponents have a 1.029 OPS against him at home and .667 away, while his strikeouts are up and walks down when pitching on the road.

Nelson has shown the ability to shut down even the best offenses when his command is right. There just have been too many feast or famine outings to always know what’s coming.

— Alex Weiner

Tommy Henry

Henry has been the steadiest of this group and it’s not particularly close.

Across his 14 starts, Henry has given up more than three earned runs only four times, even though his 1.35 WHIP isn’t the greatest and Baseball Savant has Henry’s 16.9% strikeout rate in the 13th percentile of baseball. He succeeds with that partially due to his excellent hard-hit percentage and chase percentage, which all rank highly compared to the league average.

Has he been great enough to ease the D-backs’ desire for another starter, a more formidable name after Gallen and Kelly? No. But for the back of the rotation, Henry has been great.

— Kellan Olson

Brandon Pfaadt

Pfaadt’s third opportunity in the bigs appears to be coming soon, as he is expected to start a game this weekend in Cincinnati against the Reds.

His first two big league stints left a lot to be desired, especially for someone ranked by MLB Pipeline as Arizona’s No. 1 pitching prospect. He started five games in May before getting optioned back to Triple-A Reno with an 8.37 ERA having allowed 31 hits and eight home runs. 

Pfaadt came back for a start on June 29 after making what he described as mechanical adjustments such as going through the catcher, his glove tap and getting in on righties. But his return to the D-backs lasted only six outs with six earned runs against the Rays. 

Too many middle-middle misses with the fastball has led to a 50% hard-hit rate in six starts, which is in the bottom 3% of the league, per Statcast. 

Each time Pfaadt has gone back to Reno, he’s had results. His latest start involved 5.2 scoreless innings with eight strikeouts. He has a 93-95 mph fastball with elite spin that can rise and jump on hitters. But he cannot survive leaving pitches over the heart of the plate, which has proven to be a loud message early in his career. 

— Alex Weiner

Prospects worth monitoring

The D-backs honed in on college starting pitchers early in their 2019 and 2020 draft classes. Henry and Nelson were 2019 picks who came up last year. RHP Bryce Jarvis, RHP Slade Cecconi and Pfaadt joined the organization in 2020. 

Jarvis and Cecconi both reached Triple-A this season and have started 15 and 18 games for the Aces, respectively. 

Jarvis, 25, was a first-round pick who boasts a plus slider and changeup with a mid-90s fastball. He has struck out more than a batter per inning in each stop in the minors, but his walks per nine frames have hovered from mid 4s to low 5s. 

Cecconi, 24, is the No. 9 prospect in the system by MLB Pipeline, who throws a 91-95 mph heater and plus slider. His strikeouts have gone up to 9.49 per nine innings this year while his walk rate has stayed below 7%. Cecconi is a fly ball pitcher, though, allowing more fly balls than grounders in each of the past two seasons. In Reno, many of those balls have left the yard.

LHP Blake Walston is also in the Aces rotation as a 22-year-old. Walston has kept the runs down compared to the two righties, but he has as many walks as strikeouts with 5.84 per nine. 

Walston was probable to pitch Thursday, Cecconi Friday and Jarvis Sunday, for what it’s worth.

— Alex Weiner

Names on the trade market

Due to the recent playoff expansion and how tight the final wild card spots are in both leagues, the D-backs will have some serious competition for any names they’d be chasing after to really sturdy up the middle of the rotation.

The Athletic compiled the top 100 overall names to watch at the deadline to provide an idea of who could be in talks.

The White Sox’s Lucas Giolito, St. Louis’ Jack Flaherty and Chicago’s Marcus Stroman are the trio of premium names on expiring contracts with bad teams to monitor as rentals who are possibly getting dealt.

But given the D-backs’ positive long-term outlook, targeting players under multiple years of control will be of far more interest. Will they pay up for someone like White Sox righty Dylan Cease or Tigers lefty Eduardo Rodriguez?

There has to be a balance somewhere between upgrading the position and not giving up the farm in the process. Those are the high-end pitchers, and Arizona could (and probably will) aim lower. But then the risk is that pitcher isn’t much of a difference-maker compared to what the D-backs already have.

We’ll see if general manager Mike Hazen can find that balance through an overcrowded marketplace.

— Kellan Olson

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