Sir Alex Ferguson has now confirmed his talismanic striker will be fit to face the Italians, despite declaring at the weekend that Rooney was 'a big doubt' after aggravating a knee injury on England duty last week.
Lively: Wayne Rooney (centre) in training on Tuesday morning
UNITED SQUADTeam (from): Van der Sar, Kuszczak, Foster; De Laet, Neville, Rafael,Ferdinand, Vidic, Evans, Evra, Fabio; Park, Valencia, Scholes, Fletcher, Gibson, Obertan, Giggs, Nani; Rooney, Berbatov, Diouf.
'He is fit,' said Ferguson. 'There is a rapid improvement from Saturday morning because on Friday evening I didn't think he had any chance.
'It's good news. He is a threat to anyone at the moment.'
The 24-year-old sat out United's laboured win at Wolverhampton Wanderers on Saturday, but he was pictured looking plenty mobile at Carrington this morning.
It is a huge boost for Ferguson to be able to call on his top scorer for the Champions League last 16 second leg at Old Trafford.
Raring to go: Wayne Rooney is set to line up against Milan
Return: David Beckham
United take a 3-2 lead from the first game at the San Siro in what isset to be an emotional return to his first club for Milan midfielderDavid Beckham.
Ryan Giggs also trained this morning, after having a plate removed from the arm he broke at Aston Villa recently. But the Welshman was limited to a solo session and Ferguson has already declared the winger will not come into contention.
Defender Wes Brown is also out, but his foot injury is not as bad as feared and he is expected to return in four to six weeks. Anderson (knee), and John O'Shea (leg) are also out.
United have options, with Dimitar Berbatov impressing at Molineux on Saturday, while Paul Scholes scored his 100th Premier League goal.
Michael Carrick is suspended following his late dismissal in the San Siro, so Darren Fletcher is expected to return.
The Red Devils have never been knocked out of a two-legged European tie after winning the away leg first.
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