[15] On August 1, 2016, the Dodgers traded Holmes, Jharel Cotton, and Frankie Montas to the Oakland Athletics in exchange for Rich Hill and Josh Reddick.
[18] Holmes missed over a month during the year with shoulder soreness, and split the 2019 season between Midland and the Las Vegas Aviators, going a combined 6–5 with a 3.23 ERA and 81 strikeouts over 86+1⁄3 innings.
[19][20] Holmes did not play in a game in 2020 due to the cancellation of the minor league season because of the COVID-19 pandemic.
On August 13, 2022, Holmes signed a minor league deal with the Atlanta Braves organization.
Holmes spent the 2023 season with the Triple–A Gwinnett Stripers, appearing in 50 games and registering a 7–3 record and 3.54 ERA with 74 strikeouts and 13 saves across 61.0 innings of work.
[26] He made his MLB debut later that day against the Tampa Bay Rays, pitching three scoreless innings in relief and recording two strikeouts.
[27] On July 29, Holmes made his first career start, against the Milwaukee Brewers, allowing one run in five innings while recording eight strikeouts in a no-decision.