Cape Town - Manchester United defender Marcos Rojo has undergone surgery on the shoulder he dislocated in training last week, the Argentina international confirmed via his Instagram account.
"My operation was a success. Thank you to my beautiful wife, always with me. Thank you everyone for your messages of love and support," Rojo wrote on Instagram.
Rojo dislocated his left shoulder after a fall in training - the same injury he suffered in a 1-0 defeat at Manchester City last season.
It is not known how long the 25-year-old will be on the sidelines, but British media said the defender was expected to be ruled out for four weeks.
Rojo joins a lengthy list of defensive absentees for Louis van Gaal's side, including Phil Jones and Luke Shaw.
Centre back Chris Smalling (groin) and full back Matteo Darmian (hamstring) are doubts for Saturday's Premier League trip to Bournemouth after picking up knocks in Tuesday's 3-2 Champions League loss at VfL Wolfsburg.
That defeat saw United knocked out of Europe's elite competition and relegated to the second-tier Europa League.