The Athletics optioned Barnett to Triple-A Las Vegas on Monday.
Barnett made five late-season starts for the Athletics in 2025, submitting a 6.85 ERA and 1.66 WHIP across 22.1 innings in what was his first taste of the big leagues. With the Athletics rotation in better health heading into 2026, Barnett wasn't able to clinch a spot on the Opening Day roster, but he should be one of the top candidates to get a call-up from Triple-A whenever the big club is in need of a spot starter.