Manchester United manager Louis van Gaal has warned Anderson that he must improve his fitness if he is to have a future at the club.
The Brazilian midfielder, who has been linked with a move away from Old Trafford in January, has not featured since United's goalless draw with Burnley in August.
Van Gaal says that Anderson must show a positive attitude if he is to play for the club again.
"He's now coming back," Van Gaal told ESPN. "He was injured but he's training now with the team. I cannot say what had happened last year but in my four months here, he's had a lot of injuries.
"So I cannot judge him but when he trains he trains at a good level. He's not always fit and that is more his problem now. I can't pick him now because you have to be fit.
"For the first three months the culture of a trainer is fitness. That is the smallest thing you can demand. Professional league fitness. Fitness is the most important thing. First you have to show your fitness. Not for just one day but for several weeks."
Anderson, who spent the second half of last season on loan at Fiorentina, is out of contract in the summer.
Steven Toplis
