Six weeks out for Keane

Manchester United captain Roy Keane faces six weeks on the sidelines.

The combative Irishman had been left out of United's squad to face Villarreal on Wednesday because of a hamstring niggle, sustained during Saturday's stalemate with neighbours City.

United chief Sir Alex Ferguson had hoped the knock would prove nothing serious but tests have now revealed the full extent of the injury.

Keane is expected to miss the next six Premiership fixtures, along with three games in the UEFA Champions League.

The news will do little to lighten the mood at Old Trafford, with United already trailing Chelsea having been unable to pick up maximum spoils at the weekend.

Keane's absence is likely to hand Alan Smith further opportunity to demonstrate he has all the capabilities to make his transformation from striker to midfielder a success.

Smith will play an unfamiliar holding role against Villarreal and is sure to face a tough evening trying to curb the inventive midfield promptings of Argentine playmaker Juan Roman Riquelme.

Despite a lack of experience in the position, Ferguson is confident Smith will prove himself more than capable on Europe's premier stage.

''Sadly, Roy Keane has a hamstring injury and that's unfortunate so Alan Smith will play there and it will be a big night for him,'' said Ferguson.

''A player like Riquelme is a major opponent and very skilful. He controls the tempo and everything goes through him.

''Alan can expect to be busier than he was against Manchester City on Saturday but I have a lot of confidence in him.''

Meanwhile, Wes Brown is expected to need a further three weeks before he is ready to challenge for first team football as he recovers from an Achilles injury.