The Athletics promoted Thomas from Double-A Midland to Triple-A Las Vegas on Tuesday. He went 2-for-3 with a double and a run scored in his Las Vegas debut in Tuesday's 8-4 win over Tacoma.
He took over the spot on Las Vegas' roster that was left open when outfielder Lawrence Butler was called up to Oakland on Tuesday. The 23-year-old Thomas received his first taste of the Triple-A level after slashing .282/.340/.568 with 14 home runs and 12 stolen bases in 259 plate appearances for Midland.