Morneau went 3-for-5 and collected four RBIs in the Red Wings' 8-0 shutout of the Norfolk Tides.
Playing in his third game in as many days, the 30-year-old Twins slugger singled in a run in the first inning and smacked a bases-clearing double in the second. He saw a total of five pitches in the two at-bats.
After flying out in the fourth, Morneau singled to right in the sixth. He also struck out on three pitches facing veteran lefty reliever Clay Rapada in the eighth.
Morneau, who batted cleanup, served as Rochester's designated hitter. He played seven innings of defense at first base Friday and eight more Saturday. He went a combined 1-for-8 in those, his first, rehab games.
The four-time All-Star and the 2005 American League MVP underwent surgery June 29 to remove a herniated disk fragment in his neck. Minnesota initially placed him on the disabled list due to his sprained left wrist. He is batting .225 with 16 extra-base hits and 21 RBIs in 55 Major League games this season.
Morneau and the Red Wings scored all their runs against starter Mitch Atkins (2-5), who departed before recording a third out in the second.
Rochester starter Andrew Baldwin (6-9) allowed four hits over seven scoreless innings.