Paul Pogba was forced off with an injury in Manchester United's Champions League clash with Basel - and could be out for the next six weeks.
The France international was replaced by Marouane Fellaini on 19 minutes after going to ground and gesturing to the bench.
He appeared to pull his hamstring and was visibly frustrated at having his night cut short in the Red Devils' opening Champions League group game.
Pogba, who was named Man United captain for the match by Jose Mourinho, handed the armband to Ashley Young before leaving the pitch.
Mourinho will be frustrated to lose the £90million midfielder, who left Old Trafford on crutches on Tuesday night.
Especially as this is the second time in six months the 24-year-old has suffered a hamstring injury, after he was forced off against Rostov in the Europa League.
On that occasion the France international was out for three weeks, and a repeat of this would see him miss a number of crucial fixtures.
This weekend the Red Devils host Everton before Burton Albion visit Old Trafford in the Carabao Cup.
They will then travel to St Mary's to play Southampton before heading to Russia to play CSKA Moscow. Their fifth match will see them play host to Crystal Palace before they head to Anfield to take on bitter rivals Liverpool.
Providing an update on Pogba's injury, Mourinho told BT Sport: "I don't know, I think so too [it is a hamstring injury].
"I didn't speak yet with him or the medical department but the squad are for suspensions and injuries.
"We don't cry with injuries, we had yesterday a huge attack on some of our important players [at Stoke City on Saturday], so no Paul for Sunday, but we have [Michael] Carrick, Fellaini, [Nemanja] Matic, [Ander] Herrera."