Manchester United midfielder Anderson has been ruled out for at least three weeks after suffering a hamstring injury in last weekend's win over Reading.
Anderson scored United's first goal in their 4-3 victory at the Madejski Stadium, but the Brazilian was then forced off at half-time and missed Wednesday's Champions League defeat against CFR Cluj.
â€œIt is a hamstring," Ferguson told MUTV. "It will be three or four weeks. It is not serious but it is a hamstring."