United travel to Aston Villa on Saturday after a fortnight off due to the international programme.
"There have been a lot of games for the players and we always find the match after an international break is very tough," Vidic told ManUtd.com. "It's hard to come back to the club and adapt your game - everyone plays differently on international duty. When you return to United you have to find your feet again and it can take a few days to settle."
Vidic also suggested United's non-English players find the going even tougher.
"It's very hard when I have a home international game in Serbia, for example. I get to see my friends and family, which is nice, but that can take it out of you and it means you get less time to yourself to rest.
"Then again, when I'm playing for United I feel very professional because I don't have those distractions. I have a lot of time for myself to rest, think about the next game, prepare for the training sessions. I'm very comfortable here."