The £3.9million signing is now putting pressure on 31-year-old Patrice Evra for a regular start at left-back, although the Frenchman has been first choice since he signed in 2006.
The Dutchman said: "I have played more than I had expected. New players tend to be gradually brought into the team at United.
"It is great to be on the training ground with such fantastic players everyday. It really improves you as a player."