It means the midfielder’s season is all but over, after his latest injury update this morning.
The Uruguay international was taken off on a stretcher following a tackle from Blues defender James Bolton in the 12th minute of last Monday night’s Fratton Park Cup tie.
He was then later seen leaving the ground on crutches.
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On Tuesday, the former Sampdoria ace said he was ‘fine’ in quotes attributed to ESPN.
However, the Gunners revealed on Thursday that he suffered a fracture in the 2-0 win for the Premier League side.
Torreira was replaced by Dani Ceballos just 16 minutes into match, which the Gunners went on to win courtesy of goals from Sokratis Papastathopoulos and Eddie Nketiah.
The tackle by Bolton was defended by both Tony Pulis and Jermain Jenas during their commentary of the game for BT Sport and BBC 5 Live.
Kenny Jackett also backed his player over the ‘well-timed’ challenge which incensed Arsenal fans.