Arsenal's Mikel Arteta will miss the rest the season with a damaged ankle ligament.
The Spanish midfielder sustained the injury during Monday night's 2-1 defeat to Wigan Athletic at the Emirates Stadium.
Scans taken earlier this week revealed that Arteta's ankle was not broken, but the damage has now been confirmed as severe enough to rule him out of the Gunners' four remaining fixtures.
The news leaves manager Arsene Wenger with a midfield crisis going into this weekend's game against Chelsea.
Jack Wilshere is sidelined through injury, Abou Diaby remains unfit, and loanee Yossi Benayoun is ineligible to play against his parent club.
Following their clash with Chelsea, Arsenal have Premier League matches against Stoke City, Norwich City and West Bromwich Albion.
