Cesc Fabregas has suffered a suspected broken nose while playing for Spain.
The Arsenal midfielder managed to finish the World Cup qualifier in Belgium but after the game Spain's medical staff revealed their concerns.
Fabregas will now report back to Arsenal to have the injury assessed, although it will be hoped that he can play on against Everton this weekend.
"It happened [in the first half] as I jumped with a rival, in football these things happen," explained Fabregas.
"I noticed something during the match but the team needed my help and I rejected the chance to be substituted."
Arsene Wenger will be desperate to make sure his prized midfielder is fit, as Fabrgeas himself has highlighted the issue of the club's small squad.
"Our squad is a bit short on numbers and we are very young," admitted the 21-year-old Spaniard.
"Behind me there is Denilson, who is 20, or Alex Song who is 21. Theo Walcott is 19 and Samir Nasri 21.
"It's hard to imagine a midfield where I am the oldest member.
"We find it very hard to win matches, as we do not possess enough experience.
"I scored 13 goals last season but then I had plenty of allies. Tomas Rosicky (injured) was around, Mathieu Flamini (now at Milan) covered every blade of grass and Alexander Hleb (who went to Barcelona in the summer) was like a brother to me out there.
"The team played with a lot of skilful touches, we were as solid as a brick wall and our opponents would not get a look in.
"Now none of those players are in the side and I feel like a rare being. We are more defensive-minded and sturdy as a team but we don't play so much skilful stuff."
i find he himself lack of motivation tis season... time to pass capt armband to him in order to boost his morale!