Diamondbacks Add 2 Players as Rosters Expand in New Transaction

On September 1, rosters across Major League Baseball expand from 26 to 28. The Arizona Diamondbacks have made two additions to round out theirs.

Arizona has, as expected, activated outfielder Lourdes Gurriel Jr. from the 10-day IL. Gurriel had been rehabbing an adductor strain for a lengthy period.

The Diamondbacks have also made an addition to their pitching staff, reinstating left-handed reliever Blake Walston from the 60-day IL and adding him to the 40-man roster.

To clear room for Walston, right-hander Ryan Thompson has been transferred from the 15-day IL to the 60-day IL (strained lower back).

Diamondbacks activate Lourdes Gurriel Jr.

Jun 28, 2026; St. Petersburg, Florida, USA; Arizona Diamondbacks left fielder Lourdes Gurriel Jr. (12) reacts after being hit by a pitch against the Tampa Bay Rays in the fourth inning at Tropicana Field. Mandatory Credit: Nathan Ray Seebeck-Imagn Images | IMAGN IMAGES via Reuters Connect

It has not been a productive season for Gurriel, who began the year on the IL due to an ACL tear suffered at the tail end of the 2025 season.

Once he did return, he lasted just a month and a half before suffering a hamstring strain. Once recovered from that ailment, an adductor strain forced him back to the IL for the third time this season.

After a bit of a down year in 2025, Gurriel's numbers have mostly bottomed out to a .207/.254/.287 slash and .541 OPS with two homers. He's only played in 47 games this season, however.

Gurriel's return also provides a roster crunch, with a wealth of outfield options available to Arizona. Jordan Lawlar and Ryan Waldschmidt are already limited by the presence of Max Kepler, Lars Nootbaar and Jorge Barrosa, and Tommy Troy is also on his way back from a shoulder injury.

Gurriel is expected to only play against left-handed pitching, but could provide a positive, effervescent clubhouse presence, which could be an intangible asset given the recent drama surrounding this club.

Diamondbacks activate Blake Walston

Arizona Diamondbacks' Blake Walston (48) pitches against the Texas Rangers at Surprise Stadium on Sunday, March 2, 2025. | USA TODAY Network via Reuters Connect

Walston, once a first-round-selected starting pitcher, had his 2024 season abruptly ended with a UCL sprain in his elbow. He underwent Tommy John surgery and did not pitch at all in 2025.

Walston has made six rehab appearances for Triple-A Reno — all in relief — giving up four earned runs in 7.2 innings. His ability to pitch up to two innings, and the fact that he will be only the second lefty in Arizona's bullpen, make him a potential contributor.

The 25-year-old has made seven appearances in the major leagues, pitching 18.1 innings and allowing nine earned runs for a 4.42 ERA.

Ryan Thompson will not pitch again in 2026

Aug 4, 2026; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Ryan Thompson against the San Diego Padres at Chase Field. Mandatory Credit: Mark J. Rebilas-Imagn Images | IMAGN IMAGES via Reuters Connect

Arizona's sidewinding right-hander was having another strong season out of the bullpen, but a rocky July saw him pitch to a 9.00 ERA in 11 appearances.

Thompson made two appearances in August before going on the 15-day IL with a lower back strain. Since the date of that transaction is August 5, and not retroactive, Thompson cannot be activated from the 60-day IL this season and will not pitch again in 2026.

He will finish 2026 with a 4.43 ERA, and may not don a Diamondbacks uniform again, given his expiring contract.

The 34-year-old has been a mostly-reliable back-end member of Arizona's bullpen since he was snagged off waivers in 2023, and holds a 3.51 ERA over 161.1 innings as a Diamondback, but it was clear his command — and what little velocity remained — had begun to waver in his recent appearances.

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