HENRIKH MKHITARYAN has been ruled out of Arsenal's clash with Southampton at the weekend.

The Armenian limped off midway through the second half with a knee injury in the 4-1 win over CSKA Moscow on Thursday.

Boss Arsene Wenger admitted he doesn't know the severity of the injury, but the game against relegation-threatened Southampton will come too soon.

After the game he said: "He has a knee problem.

"We don't know how bad it is, we have to assess it tomorrow morning (Friday). He will certainly be out for Sunday."

Colombian stopper David Ospina is also sidelined with an ankle issue in which Wenger feared could have been "very serious".

But the Frenchman revealed it is better than first feared following a scan.

Wenger added: "He just moved back to make a save and sprained his ankle. There was no contact.