The Argentina international picked up an ankle problem during the Red Devils’ goalless draw with Southampton in the Premier League on Sunday.
The injury turned out to be more serious than expected which means the attacker will be out of action for a long-term and return to the United first-team only after the international break.
Devastated by the news, Garnacho took to Instagram to share his feelings.
“Unfortunately I will not be able to help my team and team mates in the upcoming games in what is a very important part of the season for us at Manchester United,” the youngster wrote.
“I am disappointed to also miss the opportunity to be with my team mates of the Argentinian National Team in what would have been a great and proud moment for me and my family.”
Despite the disappointing state, Garnacho claimed he is now focused on his recovery process.
“This is part of football and our profession, however, 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!” he added.