Diamondbacks' Series vs Pirates Comes With Huge Playoff Implications

This is a big one.

Jul 22, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Merrill Kelly (29) throws a pitch against the Athletics in the first inning at Chase Field. Mandatory Credit: Rick Scuteri-Imagn Images | IMAGN IMAGES via Reuters Connect

The Arizona Diamondbacks are in the midst of a road trip that might become a determining factor in their playoff fates.

After beating the Cardinals in a one-off make-up game, they lost two out of three games to the pesky Washington Nationals. The Diamondbacks sit at 55-51, and hold a one-game lead for the third and final Wild Card spot as they barrel towards the August 3 Trade Deadline.

And the team that sits right beneath Arizona is their very same opponents for their upcoming three-game series: the Pittsburgh Pirates. It can't be called a must-win series at this stage of the season, but it's close.

Diamondbacks' series with Pirates carries playoff implications

Jul 27, 2025; Pittsburgh, Pennsylvania, USA; Pittsburgh Pirates starting pitcher Paul Skenes (30) pitches to Arizona Diamondbacks second baseman Ketel Marte (4) during the third inning at PNC Park. Mandatory Credit: Charles LeClaire-Imagn Images | IMAGN IMAGES via Reuters Connect

As it stands, the Pirates are 54-52, as are the Nationals, tied with them. The Diamondbacks lost two out of three games to Pittsburgh back in early May, so they trade 2-1 in the season series.

That, of course, means Arizona will have to win two of three to avoid losing the tiebreaker. A sweep would be the only way to earn it.

Arizona has been bit by the tiebreaker factors in the past. The Pirates are certainly a much better team this year than they have been in previous iterations, but the assignment is still simple: the D-backs have to find a way to take two games here.

If they don't, they'll be leapfrogged in the playoff picture and forced to come out of their 162-game trek with more wins than Pittsburgh should both teams remain in the race down the stretch.

The Diamondbacks won't have to face Paul Skenes, who blanked them for eight innings back on May 7. Here's what the pitching matchups look like.

Diamondbacks vs Pirates pitching matchups

Monday, July 27: RHP Merrill Kelly vs RHP Mitch Keller

Jul 17, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Merrill Kelly (29) looks on prior to the game against the St. Louis Cardinals at Chase Field. Mandatory Credit: Matt Kartozian-Imagn Images | IMAGN IMAGES via Reuters Connect

Game one is a matchup of veteran arms having underwhelming seasons. Merrill Kelly has a 5.12 ERA this season, though he's had a good month of July. Kelly has allowed six earned runs in his last 22 innings, going 3-0 with a 2.45 monthly ERA.

Mitch Keller has a 4.90 ERA this year, but most recently threw five scoreless innings with six punchouts against the Yankees.

Tuesday, July 28: RHP Brandon Pfaadt vs RHP Bubba Chandler

Jul 23, 2026; St. Louis, Missouri, USA; Arizona Diamondbacks starting pitcher Brandon Pfaadt (32) throws against the St. Louis Cardinals during the first inning at Busch Stadium. Mandatory Credit: Jeff Curry-Imagn Images | IMAGN IMAGES via Reuters Connect

Brandon Pfaadt has steadily delivered results since his return from the minor leagues. He has a 4.43 ERA that has gone down from 5.92 thanks to a 2.49 month of July. He has yet to allow more than two runs in a start since his return to the majors.

Bubba Chandler has a 4.47 ERA, but just tossed 6.1 scoreless innings in his recent start. He has walked 56 batters in 100.1 innings, for a high 12.7% walk rate.

Wednesday, July 29: LHP Eduardo Rodriguez vs RHP Jared Jones

Jul 19, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Eduardo Rodriguez (57) throws against the St. Louis Cardinals in the first inning at Chase Field. Mandatory Credit: Rick Scuteri-Imagn Images | IMAGN IMAGES via Reuters Connect

Eduardo Rodriguez got back to his All-Star ways his last time out with six-innings of two-run baseball against a potent Nationals lineup. He has a 2.64 ERA and has been the D-backs' best starter all season. He was responsible for Arizona's lone win over Pittsburgh this season with seven scoreless innings on May 5.

Jared Jones has returned from internal brace surgery (Tommy John variant) with mixed results. He's hit his stride this month, however, with a 1.29 July ERA and a 3.72 figure for the whole season. He has 53 strikeouts in 46 innings.