Shkodran Mustafi is doubtful for Arsenal's FA Cup fifth round encounter against Portsmouth on Monday night.
The defender - who has been one of the Gunners' better performers since the appointment of Mikel Arteta as head coach - was forced off in extra-time during the disappointing Europa League round of 32 defeat by Olympiacos on Thursday.
It was confirmed afterwards that the German could have been suffering with cramp.
"I don't know," head coach Mikel Arteta said in his post-match press conference at the Emirates Stadium.
"He said to me 'I cannot play anymore'.
"I don't know if it's a cramp or a muscle injury so I'm sure there will be a few of those because the players were exhausted, they played four times in seven days and it was physically a very demanding game."
Sokratis replaced Mustafi in the first-half of extra-time but couldn't prevent the hosts from crashing out of the competition as he was partially at fault or Youssef El-Arabi's goal which meant Olympiacos went through on away goals.
Attentions now turn towards another cup competition as the north London outfit aim to get back to winning ways in their bid to finish the season strongly.
Having failed to see out the Olympiacos game naturally Mustafi is considered doubtful for the game at Fratton Park.
But it would appear Mustafi is in good spirits.
Taking to social media after the Olympiacos game, he somewhat broke his silence following the injury scare without saying too much.
"It's a hard one to take for everybody but in difficult moments we have to stick together," he wrote on Instagram. "Always grateful for your support."
Whilst it's not confirmation that the injury is not too serious, the fact there was no mention of the problem that forced him off against Olympiacos could be a positive sign.
With that said, losing Mustafi for an extended period could allow Arteta to hand Pablo Mari a first-team debut.
The central defender joined on loan in the January transfer window, but has been limited to 45 minute appearances for the U23's against Chelsea and Manchester City so far.
