Nemanja Matic, Ander Herrera, Eric Bailly and Antonio Valencia were conspicuous by their absence as Manchester United trained on the eve of their Champions League quarter-final meeting with Barcelona.
A week after losing 2-1 at Wolves in the Premier League, Ole Gunnar Solskjaer's side are preparing to bounce back when Barca visit Old Trafford for Wednesday's first leg.
Herrera, Bailly and Valencia missed United's last match through injury and look set to be unavailable once again, with the trio absent from the open part of the session at the Aon Training Complex.
Matic was an unused substitute at Wolves, but was another notable absentee on Tuesday morning.
Alexis Sanchez was back with the group after a knee injury picked up against Southampton five weeks ago, while Marcus Rashford was involved in the session after missing the trip to Molineux with an ankle complaint.
However, the 21-year-old's fitness is unclear after starting the session doing individual work before joining in with the main warm-up.
Youngsters like Tahith Chong and Mason Greenwood trained separately from the main group.
Chris Smalling is due to join manager Solskjaer for the pre-match press conference at Old Trafford at 2pm.
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