Jose Mourinho admitted Manchester United are in "trouble" following serious knee injuries to Zlatan Ibrahimovic and Marcos Rojo amid a growing injury crisis at Old Trafford.
Ibrahimovic and Rojo are feared to have suffered season-ending knee injuries in Thursday's Europa League quarter-final victory over Anderlecht.
The pair join a long list of casualties at the Premier League club, with Chris Smalling, Phil Jones and Juan Mata already on the sidelines.
And manager Mourinho is genuinely worried as United try to qualify for next season's Champions League via a top-four finish in the Premier League or by winning the Europa League, where they will meet Celta Vigo in the semi-finals.
"We are in trouble," Mourinho said ahead of Sunday's trip to Burnley. "We are in trouble.
"In this moment, Eric Bailly played six matches in a row, and we lost Marcos Rojo, we don't have Jones or Smalling, we are in trouble and now we lose Zlatan too.
"But in attack, we have options and [Wayne] Rooney is coming, and let's see if Mata can also return before the end of the season, let's see what happens."
United are fifth in the Premier League, four points adrift of rivals Manchester City with seven matches remaining.