"We are well covered in those positions," the 57-year-old told ESPN FC ahead of the club's summer tour to the United States. "Even with Robben picking up a little injury, he'll be ready for the start of the season, so all positions are really well covered. We don't need another player, we are enough and we are competitive."
Varela, 23, came on as a substitute during Jose Mourinho's first game in charge, a 2-0 win against Wigan, but did not travel to China for United's preseason tour.
With Matteo Darmian, Antonio Valencia and Timothy Fosu-Mensah all ahead of Varela in the right-back pecking order at United, Mourinho was willing to let the Uruguayan leave for the Bundesliga in order to find regular football.