Manchester United midfielder Anderson has admitted that he is frustrated with his lack of progress at the club.
The Brazilian is not a regular in Sir Alex Ferguson's side and he feels that a good run is often ended with a disappointing setback at Old Trafford.
"When I take two steps forward I seem to take three back," Anderson is quoted as saying in The Telegraph.
"It is sad but I have to do my job. I need to play and not to have any injuries.
"I have had some problems. But when I don't have these problems I know my quality. I know I can play."
Anderson was signed from FC Porto in 2007.
