http://news.bbc.co.uk/sport1/hi/football/teams/m/man_utd/7846732.stmanchester United will be without Anderson and Jonny Evans for three weeks because of ankle injuries.
Midfielder Anderson, 20, and defender Evans, 21, were both stretchered off during United's Carling Cup win over Derby on Tuesday.
"Anderson went for a scan and there is no break," said Mr. Ferguson. "But there was some ligament damage. We think he will be out for three weeks.
"Jonny Evans will also be out for three weeks," added the United boss.
Rafael and Nani were also injured against the Rams and Ferguson confirmed that they will be missing for United's FA Cup clash with Tottenham on Saturday.
Right-back Rafael was forced off just before half-time at Old Trafford and it is thought he could be missing for up to a month, while Nani suffered a groin injury and will be out of action for a week.
"The ones who are out (for the Spurs game) are Rio Ferdinand, Anderson, Nani, Rafael, Patrice Evra, Wayne Rooney, Wes Brown, Jonny Evans and Ji-sung Park," added Ferguson.