Louis Saha has been ruled out of Manchester United's Champions League quarter-final decider against AS Roma with a hamstring injury.

The Frenchman's only appearance in the last month was as a late substitute in the first leg in the Olympic Stadium and had been expected to play more of a part in the return leg at Old Trafford on Tuesday.

However, Saha suffered a recurrence of his injury in training ahead of Saturday's Premiership defeat to Portsmouth at Fratton Park and Sir Alex Ferguson, the United manager, feels it is not worth risking him, despite his side needing to overcome a one goal deficit.

"We have to err on the side of caution," Ferguson said. "There is no point bringing someone back who is not 100 per cent fit and risk further injury."

United will also be without suspended midfielder Paul Scholes, plus long-term absentees Gary Neville (ankle), Nemanja Vidic (collarbone) and Mikael Silvestre (shoulder). Ji-sung Park is also ruled out for at least a fortnight after suffering a knee injury in the win over Blackburn on March 31.

"We are still assessing Ji-sung to see what we do next with him," Ferguson said. "Hopefully the news will be good and he will only be out for a couple of weeks."

Manchester United (from): Van der Sar, Kuszczak, O'Shea, Brown, Ferdinand, Cathcart, Heinze, Evra, Ronaldo, Fletcher, Carrick, Eagles, Giggs, Richardson, Solskjaer, Smith, Rooney, Dong.