Eaton is leading off and playing center field for Tuesday night's game against Cleveland.
Eaton, 25, was placed on the disabled list Aug. 9 with a strained right oblique. He went 3 for 10 in two games with Triple-A Charlotte on a rehab assignment.
In 94 games in his first season in Chicago, Eaton is hitting .304 with seven triples and 55 runs scored. He was on quite a roll before the DL stint, hitting .435 in his previous 22 games.
Eaton takes the roster spot of outfielder Jordan Danks, who was sent down to Charlotte on Monday.