Alejandro Garnacho has vowed to come back "stronger than ever" after being ruled out for Manchester United and world champions Argentina due to an injury suffered against Southampton on Sunday.
The 18-year-old forward was withdrawn 17 minutes after stepping off the bench in the second half of United's 0-0 draw following a challenge by Southampton's Kyle Walker-Peters.
Garnacho, who left Old Trafford on crutches, said on Instagram that he will miss "upcoming games" for United and will not be joining up with Argentina's squad for friendlies against Panama on March 23 and Curacao three days later.
"It is difficult to put into words how I'm feeling right now," the Under-20 international wrote on Instagram.
"Unfortunately I will not be able to help my team and teammates in the upcoming games in what is a very important part of the season for us at Manchester United."
Garnacho, who was born and raised in Madrid, said he was disappointed to miss out on the chance to join up with World Cup holders Argentina, saying it would have been "a great and proud moment for me and my family".
"This is part of football and our profession, however," he said. "I am already focused in my recovery.
"God has taught me to never give up and I will make sure I am back stronger than ever."
United boss Erik ten Hag said after Sunday's game that he did not think Garnacho's injury was "too bad".
Neither the player nor United have specified what the injury is or how long he will be out for.
The teenager has enjoyed a breakthrough season at Old Trafford after making his Premier League debut in April last year against Chelsea, scoring four goals in 29 first-team appearances in all competitions.