Lucas Torreira is unlikely to play again this season after Arsenal confirmed he will miss up to ten weeks as he recovers from a fractured ankle.
The Uruguay midfielder was taken off on a stretcher early on during the 2-0 FA Cup win at Portsmouth last week and was later seen leaving Fratton Park on crutches.
A fracture was confirmed by Arsenal late last week but no return date was set until the 24-year-old had seen a specialist - with further information released on Monday now ruling him out for between eight to ten weeks.
Speaking on Thursday ahead of the weekend win over West Ham, Gunners head coach Mikel Arteta had said he was hoping Torreira would be able to play again this season.
But that now looks highly unlikely given the diagnosis and how long it would then take him to get back up to speed. The Premier League season is due to end on 17 May.
The former Sampdoria man had not previously started for Arsenal since the 2-2 Premier League draw at Chelsea on 21 January but was left injured after a challenge by Portsmouth defender James Bolton, which referee Mike Dean deemed to be a fair one.
Torreira was replaced by Dani Ceballos just 16 minutes into the cup tie, which Arsenal went on to win courtesy of goals from Sokratis Papastathopoulos and Eddie Nketiah.
Ceballos and Granit Xhaka have formed Arteta's preferred midfield pairing in recent games, with Matteo Guendouzi also an option.
Saturday's 1-0 victory over West Ham left Arsenal in ninth spot, five points behind fifth-placed Manchester United with a game in hand - which comes away at Manchester City on Wednesday night.