Giants vs Diamondbacks: Rotation collapse sets tone

Giants-Dbacks rotation – San Francisco enters a three-game set at Chase Field against Arizona with a struggling offense and a matchup that could hinge on one thing: the Diamondbacks’ battered rotation. The Giants’ projected path runs through facing Eduardo Rodriguez, Zac Gallen, Ryne

By the time the Giants start lining up their bats, the bigger story in this series is already written in the numbers—especially Arizona’s pitching.

Arizona enters this matchup with a rotation that looks like it has been stitched together from ERAs that don’t match the kind of season a playoff chase typically requires.. The Diamondbacks will send Eduardo Rodriguez. Ryne Nelson. Tyler Mahle and Merrill Kelly to the mound across Monday. Tuesday and Wednesday. and each start comes with a different flavor of trouble: walk-heavy risk. home-run vulnerability. and late-inning uncertainty.

San Francisco, meanwhile, isn’t arriving with the sort of lineup that can erase pitching problems on its own.. The Giants’ offense is described as disappointing, and their production is running about 10% worse than league average.. As a team. Arizona has only 3 more home runs than the Giants (40 to 37). and Arizona’s wRC+ sits at 95—sub-average offensive production—despite a season that has been powered by Corbin Carroll’s MVP-caliber start. a resurgent Nolan Arenado. a surprise run from journeyman Ildemaro Vargas. and Ketel Marte’s presence in the lineup.

But the test for both teams begins with starters.

The Giants have managed solid performances from three starters—Robbie Ray. Landen Roupp and Trevor McDonald—while Arizona has two starters with solid output—Eduardo Rodriguez and Michael Soroka—when value is broken into the rotation versus the bullpen.. On the reliever side. Arizona’s bullpen has an edge in avoiding walks by 1.75 BB/9 and also strikes out batters a bit better than the Giants’ pen. giving Arizona a slight advantage in run-prevention value by around a win above replacement.

Defense complicates the picture in a way that could matter in a tight series. Arizona has been great on defense at +5.5 Defensive Runs Above Average, 6th in MLB, and a full 10 runs (or 1 win) better than the Giants, who sit at -5.5 Def.

So if you’re trying to find where the series swings, it comes back to the rotation collapse on the Diamondbacks’ side—because that’s where the Giants’ bats could finally get their opening.

Here is what that rotation looks like on paper:

Eduardo Rodriguez: 2.53 ERA
Ryne Nelson: 5.40 ERA
Michael Soroka: 3.49 ERA
Zac Gallen: 5.02 ERA
Merrill Kelly: 5.91 ERA

Eduardo Rodriguez’s background is part of why this set feels so loaded.. He was a hot commodity around the 2023 trade deadline before he made it clear he didn’t want to be traded.. The Diamondbacks signed him that offseason, and in the first two years of the deal, he posted a 5+ ERA.. This is the year Arizona is finally seeing strong positive value—yet his 2.53 ERA is described as misleading because it’s “betrayed” by a 3.85 ERA.

And there’s a wrinkle the Giants won’t get to experience: Rodriguez will not be seen in this series.

Michael Soroka is a different type of story. He’s back with Arizona after his career was derailed by injuries with Atlanta, and the season is framed as a great reclamation project. The Giants, too, will miss him.

Zac Gallen, whose free-agency storyline included drama, has returned looking like the worn-out arm from last year. Ryne Nelson has also come up with inconsistency: he has frustrated the Giants before, going 2-0 with a 3.05 ERA in 44.1 IP, but he has also allowed 9 home runs in 9 starts.

Merrill Kelly’s season has been rough at 37 years old. and the context is sharp: he was traded to the Rangers at the last deadline and then re-signed with Arizona.. The Giants are told to treat his recent output with care—his last start was a complete game in Colorado where he gave up a solo home run.. The start before that included 7 innings of 1-run ball at home against the Mets.

That brings the series to the most basic question for fans: are the Giants’ bats heated up enough to do damage against a staff that has been struggling?. The matchup is framed around “How Devers. Adames. and Chapman do” against a “Please Hit Me” trio of starters—an implied measure of whether the Giants can punish Arizona when pitching takes a step backward.

In Arizona’s lineup, the constant threats are Corbin Carroll, Ildemaro Vargas, and Nolan Arenado.. Ketel Marte is still 20% below league average, and Gabriel Moreno is around 25% worse.. Shortstop Geraldo Perdomo has a slow start in 2026. described as backing up his 7-WAR 2025 with a sub-100 wRC+ and -100 points of slug.

Lourdes Gurriel Jr. was close to league average last season at 95 wRC+, but he has been much worse this season at 61 wRC+. Still, he’s 6-for-his-last-17 with 2 doubles and a homer.

The concern for San Francisco is what happens if multiple Arizona bats click.. The series is positioned as a test of whether the Giants’ ability to frustrate NL West opponents—often discussed in the context of the Dodgers and Padres—translates when the Diamondbacks look. on paper. like they could frustrate the Giants instead.

The schedule is straightforward. Who: San Francisco Giants (20-27) at Arizona Diamondbacks (22-23). Where: Chase Field in Phoenix, Arizona. When: Monday & Tuesday at 6:40pm PT, Wednesday at 12:40pm PT. National broadcasts: None.

Projected starters set the tone:

Monday: Robbie Ray (LHP 3-5, 3.04 ERA) vs. Zac Gallen (RHP 1-4, 5.02 ERA)
Tuesday: Landen Roupp (RHP 5-4, 3.49 ERA) vs. Ryne Nelson (RHP 1-3, 5.40 ERA)
Wednesday: Tyler Mahle (RHP 1-5, 5.59 ERA) vs. Merrill Kelly (RHP 3-3, 5.91 ERA)

For Arizona, the lineup stories go beyond the big names.

Ildemaro Vargas. listed at age 34. is described as having the best season of his career on his third stint with the Diamondbacks.. In 2026, he went to Arizona’s Spring Training as an NRI and earned his way onto the major league roster.. He has a .903 OPS so far this season and has hit about as well as Munetaka Murakami. Bryce Harper and Nick Kurtz.. Vargas has always done fine against the Giants, with a career .720 OPS.

Nolan Arenado’s move to Arizona is also laid out with cold financial detail: the Cardinals tried hard to trade him the past two offseasons. and a taker finally emerged in the Diamondbacks.. Arizona will pay him $11 million of the $42 million owed to him over this season and next.. In 2022, he was worth 7.2 fWAR, but across the three seasons that followed he produced 6.8 total.. In his age-35 season, he’s hitting 25% better than league average (125 wRC+) thanks to a .798 OPS.. The article notes that while he’s no longer the demigod defender at the hot corner. the Giants have seen unbelievable defensive plays from him over the years.

The closer situation adds another potential opening.. Paul Sewald was compared to a closer who “backed into” the role by accident.. Arizona traded for him in 2023 as part of their World Series run.. He was on the team in 2024, but fell apart as their closer and left as a free agent.. He played for two teams last season, then the Diamondbacks re-signed him this past offseason to return as closer.. He has 1 blown save on record. but 4 losses already—enough for the Giants to wonder if late innings could present an opening.

Daniel Susac is framed as the kind of lineup question that shifts attention from defense catchers of the past.. The piece describes the idea that Buster Posey shoved aside Patrick Bailey for Daniel Susac because of batting average. and it points to the Diamondbacks-Giants history that used to feature two of the best defense catchers in the sport: Bailey versus Gabriel Moreno.. Now the focus has become whether Susac can hit.

Jung Hoo Lee’s season arc is included with specifics: he ended April slashing .297/.344/.441, but fell off in May.. His pinch-hit RBI single in yesterday’s win raised his May line to .215/.250/.292.. He has a career .607 OPS at Chase Field. suggesting the slump could last longer. especially because the rotation has been described as “Athletics/Rockies/Nationals bad.”

Robbie Ray’s previous season history with Arizona is also part of the watching.. In 5+ seasons for the Diamondbacks, he made 147 starts and one All-Star appearance.. He has a 3-0, 3.15 ERA in 3 starts (21 IP) against his former team, including a 102-pitch complete game last July.. The start is framed through trade speculation: players in form against a former team often become the center of “players who will be traded this season” conversations. and his value is described as likely landing in a range similar to Tyler Rogers’ return for the Giants—2-3 prospects near the bottom of a trading team’s top 10 or outside of it altogether.

There’s even a nod to Bryce Eldridge, thrown in because either as a pinch hitter or a starter, Arizona’s righties would seem to offer options for someone trying to get going, with the warning that the rotation gives up a lot of home runs.

The series also comes with managerial texture.. The article references a moment before the Vitello hire when Torey Lovullo’s job felt maybe not so secure despite a World Series appearance two years prior.. It describes how the Giants might have tried to poach Lovullo like Bruce Bochy from San Diego. and it adds that Lovullo’s modest success in Arizona is described as 686-715 a month and a half into his 10th season with two postseason appearances.. The piece says Buster Posey would want a player-centric. stats-second approach. and it notes that didn’t happen; instead. the Giants signed a guy whose name “sort of sounds like Torey Lovullo.” It then pivots to the point that those are rough numbers from Arizona’s starters. and that it stands to reason the Giants should win a game in the series for that fact alone.

That’s the mood right now: a matchup where the Diamondbacks’ defense and bullpen can keep games close, but where the rotation has the kind of volatility that turns a lineup into a test. When the first pitch comes at 6:40pm PT on Monday, the Giants won’t just be trying to score.

They’ll be trying to prove they can punish a staff that’s been leaking runs—before Arizona’s best bats and best moments take over the story.

Giants Diamondbacks Chase Field Corbin Carroll Nolan Arenado Ildemaro Vargas Eduardo Rodriguez Zac Gallen Ryne Nelson Merrill Kelly Robbie Ray bullpen MLB