Anderson believes Evra has struggled at the start of the season.
He told the Manchester Evening News: "Obviously, Patrice Evra has to rediscover his form. He didn't have a great season last year and hasn't really been himself this term so far.
"He has to up his game and I think the presence of Alex Buttner from Vitesse Arnhem will eventually bring out the best in Patrice again.
"He knows now if he doesn't rise to the challenge then there is a player who will take his place. Pat is in a vulnerable position at the moment but it is nothing sinister and you just have to react.
"It doesn't matter how old or experienced you are if you lose confidence then you'll have problems. But I am sure he will get it back."