Vidic hopes to be fully recovered from knee surgery for preseason training.
When asked by MUTV if it may be hard to win his place back, he replied: "Definitely. Jonny [Evans] has had a great year. I think Chris [Smalling] as well, before he got injured, is looking for that position as central defender. Rio [Ferdinand] is fit after a long time and was fit for so many games so we now have really big competition next year.
"I don't mind that. I don't think any player minds that. It makes you train harder, play better and obviously we have so many games during the season that we need good players."