Laurent Koscielny may have broken jaw - Arsenal boss Unai Emery
Arsenal boss Unai Emery fears defender Laurent Koscielny suffered a broken jaw during the Gunners' FA Cup fourth round defeat by Manchester United.
Koscielny tangled with Romelu Lukaku before the Belgian inadvertently caught him on the head during the 3-1 loss.
There was an eight-minute stoppage in the second half as the France international received treatment.
The 33-year-old had returned from a seven month absence in December after rupturing his Achilles last May.
"It was maybe a break," said Emery.
"I hope not but he's going to the hospital and we're going to wait."
Fellow defender Sokratis Papastathopoulos also left the field with an ankle injury, less than a week after full-back Hector Bellerin was ruled out for the season with a ruptured anterior cruciate ligament.
"Sokratis hurt his ankle - I hope not a lot. I hope they are not two big injuries.
"We are taking a lot of big injuries, like Hector Bellerin. Our injuries changed our possibility to do something different."
'We need to think about the Premier League'
A quick-fire double put Manchester United in control at Emirates Stadium, though Pierre-Emerick Aubameyang responded for the hosts before half-time.
However, the injury-struck Gunners - who maintain hopes of silverware in the Europa League - failed to level before Anthony Martial sealed the contest with eight minutes remaining.
And the Arsenal manager wants his side to refocus on their top-four ambitions as they prepare to host Cardiff City on Tuesday.
"Our gameplan worked well, we had pressure and chances but in the second half we can take some risk," said Emery.
"We need to think about the Premier League. We won against Chelsea and are close. We need to push in that competition and we have another important competition in the Europa League.
"We played a team in a good moment. We lost this match but I'm happy with our work. We deserved more."