Ilkay Gundogan is likely to miss the remainder of the season after tearing the cruciate ligaments in his right knee.

Manchester City acquired Gundogan from Borussia Dortmund for £20 million in the summer and his debut was delayed until mid-September because of the dislocation he suffered to the same knee.

Gundogan’s injury may prompt Pep Guardiola to bolster his midfield options in January’s transfer window.

Jan Oblak will require surgery to correct a dislocated shoulder that could lead him to miss three to four months.

Oblak will likely miss the first leg of Atletico's Champions League tie in late February against Bayer Leverkusen.

Oblak was injured while attempting to prevent Jonathan dos Santos from scoring Villarreal's second goal and was replaced in the 40th minute by Miguel Ángel Moyá.

Santi Cazorla will miss at least three more months due to surgery on his injured Achilles.

Cazorla has been absent since picking up the injury in his right ankle in the 6-0 Champions League victory against Ludogorets in October.

“Santi Cazorla is travelling to Sweden early next week to undergo surgery to his right ankle,” read an Arsenal statement on Thursday.

“The club’s medical team and specialists have decided that surgery is required to the plantaris tendon in the Spain international’s right foot.

“The problem has not progressed during a rehabilitation programme following the injury during the home match with Ludogorets on October 19. We expect Santi’s full recovery to take approximately three months. Everyone at the club will be working hard with Santi to make sure he’s back on the pitch as soon as possible.”

The surgery is coming almost six weeks after Cazorla sustained the injury.