Manchester United boss Sir Alex Ferguson may rest Ruud van Nistelrooy until the FA Cup final on 22 May to allow his knee problem to settle.
Van Nistelrooy has been struggling with a knee injury
United have Premiership games against Chelsea and Aston Villa before the trip to the Millennium Stadium in Cardiff.
But Ferguson is thought to be reluctant to risk the Dutch striker ahead of what is United's only chance of silverware this season.
The United manager has already conceded second spot in the league to Chelsea.
Van Nistelrooy has been struggling with a persistent problem to the right knee he damaged before moving to Old Trafford in 2001.
He has played in only one of United's last seven games and picked up the injury in the 1-1 draw with Arsenal in March.
The striker's knee is said to have swollen up and, despite extensive treatment, has failed to improve.
Dutch international Van Nistelrooy is also desperate to be fit to play for Holland during this summer's European Championship in Portugal.
He missed out on Euro 2000 because of the ruptured cruciate ligament injury that delayed his £19m transfer to United.