Rojo, who had been enjoying a run in the first-team, suffered the injury in training last week.
The decision was made in an effort to prevent the problem recurring as the Argentine suffered the same injury against Manchester City last season. Van Gaal provided an update on Rojo’s fitness, as well as Morgan Schneiderlin’s.
“These injuries are very heavy – [Luke] Shaw and [Antonio] Valencia have also been operated on and that’s our problem.”
United’s injury list is growing and van Gaal’s small squad is being stretched to it’s limits.
It is likely that the Dutchman will again turn to Guillermo Varela and Cameron Borthwick-Jackson for the game against Bournemouth this weekend. The pair performed admirably against Wolfsburg this week and they will need to be prepared to be thrown in at the deep end once again at Dean Court.