Thomas, 29, takes over for Chris Colabello on the 25-man roster. Colabello was sent back to the Red Wings after the Twins 10-0 win over Seattle Sunday afternoon.
Thomas, who also played for Detroit, appeared in 12 games with the Twins in 2012 after being claimed off waivers. He was eventually sent to the minors after hitting just .143.
This year, Thomas is off to a somewhat robust start in Rochester, hitting .296 with nine homers and 25 RBI in 36 games.