Manchester United veteran Rio Ferdinand trained Monday but fellow defender Rafael is a doubt for Tuesday's Champions League quarter-final first leg at home to Bayern Munich after missing the practice session.

Right-back Rafael came off at half-time during United's morale-boosting 4-1 Premier League win against Aston Villa at Old Trafford on Saturday and did not take part in the 15-minute session open to the media at Carrington, the club's training ground, on Monday.

But there was better news for Premier League champions United in the fact that centre-backs Ferdinand (back), Chris Smalling (hamstring) and longstanding absentee Jonny Evans (calf) were all on show at Carrington.

And left-back Alex Buttner, who ended the Villa match with a hamstring complaint, also trained as did winger Antonio Valencia, who missed last weekend's victory with a knee injury.

As expected, star striker Robin van Persie, who earlier this month was ruled out for four to six weeks with a knee problem, did not train Monday and nor did either the suspended Patrice Evra or England midfielder Tom Cleverley.

For United, 17 points behind Premier League leaders Chelsea and 10 adrift of the top four, winning the Champions League effectively represents their last chance of silverware this season and the club's best chance of qualifying for next term's edition of Europe's elite club competition.

But having suffered a stumbling first season under new manager David Moyes, following the retirement of British football's most successful manager in Alex Ferguson, United will be huge underdogs when they face Champions League holders Bayern in the first leg of their last eight clash at Old Trafford on Tuesday.

Last week the German giants won their domestic Bundesliga title with seven games to spare but Bayern will arrive in Manchester without midfielder Thiago Alcantara, who suffered a knee injury during Bayern's 3-3 draw with Hoffenheim on Saturday.