Marcus Rashford will be sidelined for several months after Ole Gunnar Solskjaer revealed the Manchester United striker is "touch and go" to play again this season.
Rashford, 22, suffered a back injury in United's FA Cup third-round replay win against Wolves in January.
It was initially thought Rashford would be out for around six weeks, but United manager Solskjaer said it is not impossible the England forward could now miss the rest of the season and Euro 2020.
"I would hope he's playing this season but it'll just be touch and go towards the end," Solskjaer told British media as he prepared for Thursday's Europa League last 32 first leg clash Club Brugge.
"So hopefully we can go through and get through this tournament and prolong the season.
"It takes time. I'm not a doctor, but obviously I was hoping that he would recover quicker than it actually looks like he's going to be out for. So, another few months definitely."
Pressed on whether Rashford would be out of contention for play for England at the Euros, Solskjaer said: "Well, I would hope that he plays before then but we're not sure, so if he's not fit enough he won't go."
Rashford, who came off with a back injury against Norwich just days before the Wolves match, had been confident of being "back before the season ends" shortly after sustaining the injury last month.
But Solskjaer conceded the injury was worse than United had first anticipated.
"He had a scan and it was maybe more severe, that fracture, than what we hoped for and expected because he felt fine the few days before that," Solskjaer said.
"I've never had anatomy (classes) in school so I didn't know it just takes that time to recover.
"But when he recovers, when he's healed, he'll be stronger for it, so it's important that we don't rush him. And we won't do that."
United midfielder Paul Pogba also remains sidelined, with the France midfielder's recovery from an ankle injury continuing against a backdrop of speculation about his future.
Pogba's agent Mino Raiola has fanned the flames with controversial comments amid talk of a potential move to Real Madrid and Solskjaer does not expect his player to return any time soon.
"He's not been part of team training yet, so it'll depend on how he feels or when he feels ready to do that. He's not anywhere near that yet," Solskjaer said.