The 25-year-old midfielder will be on loan at the Black Cats until January when the deal will be made permanent.
McManaman left Sunderland for Wigan in July, and the 27-year-old former West Bromwich Albion winger has congratulated Power on his move to the Black Cats.
Power himself has taken to Twitter to send messages to Wigan and Sunderland following his move.
The memories I’ve made. The club is in great hands with Paul Cook and his staff and a great set of players who i am going to miss. My children have become Wigan fans and the club will always hold a special place in my heart.— Max Power (@mp_1825) August 10, 2018
Wigan fans are a special bunch, quick to tell you when you’ve had a stinker, but make you feel 10 feet tall after a win. That night against Man City in the fa cup will live long in the memory as will promotion days at Blackpool & Doncaster.— Max Power (@mp_1825) August 10, 2018
Sunderland got relegated from the Championship at the end of last season, and the Black Cats will be aiming to win automatic promotion from League One.
As for Wigan, the Latics won the League One title last season and will be aiming not to get relegated from the Championship, but it is going to be hard for them.