Manchester United defender Luke Shaw is set for a long spell on the sidelines after suffering a double fracture in his right leg against PSV Eindhoven in the Champions League on Tuesday.
The England international was caught in a challenge with Hector Moreno when bursting into the box in the 15th minute. Although Moreno won the ball, the momentum of his tackle saw him catch Shaw with his follow through.
United confirmed the extent of his injury after PSV's 2-1 win in the Netherlands, saying he would have surgery when he returned to Manchester.
Shaw, who had an injury-plagued first season at United but was getting back to his best form, fell to the floor in pain and players from both clubs gestured to the bench for medical assistance.
The player was eventually stretchered off after a 10-minute delay.
United manager Louis Van Gaal said he hoped Shaw would be able to return before the end of the season.
"He has a double leg fracture and he shall be operated on in Manchester," Van Gaal said after the game.
"He was an 18-year-old boy who came to Manchester and his first season was very difficult. Then he has a fantastic second season and this happens.
"When he came into the dressing room, he had an oxygen mask and was crying.
"I'm not a doctor so I cannot say, but when you have a double fracture it is four to six months. But you can never say that in advance.
"He won't play in the group stage, I don't think. I hope he will play again this season."
While the game was still proceeding, Shaw responded to a tweet from his former club Southampton, thanking them for their support:
@SouthamptonFC thank you , you don't know how much you as a club mean to me , thank you so much I really appreciate it
- Luke Shaw (@LukeShaw23) September 15, 2015
He later sent out a message to fans and hinted at his condition.
Thank you everyone for your messages , words can't describe how gutted I am , my road to recovery starts now, I will come back stronger.
- Luke Shaw (@LukeShaw23) September 15, 2015
Shaw's team-mate Adnan Januzaj, currently on loan at Borussia Dortmund, wrote on Twitter:
Horrible to see what happened ���� I wish u all the best my brother and stay strong you will comeback even stronger ���� @LukeShaw23
- Adnan Januzaj (@adnanjanuzaj) September 15, 2015
Louis van Gaal looked upset at seeing the 20-year-old being carried off on a stretcher as Marcos Rojo replaced Shaw on United's back line.
The United manager went over to the defender and gave him a pat on the shoulder as he was carried down the tunnel. He was then taken to hospital as both sets of fans applauded as Shaw left the field.
Moreno was not penalised for the tackle, which happened in the PSV penalty area.
Van Gaal was clearly unhappy with the challenge but refused to condemn the Mexican defender, who played for him at AZ Alkmaar.
"If I say it is a penalty and a red card I am a bad loser, every word is interpreted in the wrong way," Van Gaal said. "But it was a very bad tackle with two legs."
PSV coach Phillip Cocu defended Moreno, saying: "The intention was not to injure the opponent."