Manchester United manager Sir Alex Ferguson rates Paul Scholes as "doubtful" for Monday's Barclays Premier League showdown with Arsenal at Old Trafford.
The veteran midfielder has not featured since the victory over Rangers last month, when he picked up a groin injury.
Scholes had been expected to play some part in United's 1-1 draw with Valencia at Old Trafford last night but, after a minor setback in training, Ferguson fears he will not be able to call upon his influential playmaker against Arsene Wenger's men.
"Paul tried training on Sunday and came off," Ferguson told MUTV.
"He will be doubtful for next Monday."
The United camp are rather more optimistic about Rio Ferdinand, who was forced out of last night's game five minutes into the second half after feeling some discomfort in his hamstring.
"Rio felt it at half-time," said Ferguson. He wanted to try it but it still felt tight.
"We weren't prepared to take a chance. There was no point because we had Chris Smalling to come on.
"He has six days and I am sure he will be okay for Monday."
The United boss was full of praise for goalscorer Anderson, who netted for only the second time in 109 appearances for the club when he tucked home the rebound to a powerful Park Ji-sung strike as the Red Devils secured the draw they required to top Group C.
After a long period on the sidelines due to a cruciate ligament injury, it was Anderson's third start in a row.
And although the Brazilian's form dipped at West Ham last week, Ferguson is delighted with his contribution.
"Anderson has been absolutely brilliant in the last three games," said Ferguson.
"He has been tremendous. He offers something different from the other midfield players we have got.
"He has tremendous pace, can beat a man and is always decisive in his passing."
Now Ferguson is looking for more of the same from the former Porto star.
"He should score more," he said.
"The boy has terrific talent. He has great pace and power. He is a strong boy.
"We are pleased he got a goal. It may help him."