Manchester United may have to contend with yet another injury concern after Ander Herrera was forced off against Stoke City.
Herrera, 25, provided the assist for Marouane Fellaini's opener in United's 2-1 win over Mark Hughes' side but was replaced by Darren Fletcher with five minutes remaining.
The midfielder was starting his first game for the club since October and with the Old Trafford club defending a narrow lead, Fletcher's introduction was initially seen as an effort to maintain United's position in the dying minutes of the game.
But United are now braced for what could be their 43rd injury of the season after the club suggested during their live coverage of the game on Tuesday 2 December that Herrera had suffered a "slight knock".
Herrera suffered fractured ribs in United's 2-2 draw with West Bromwich Albion on 22 October and despite taking a place on the bench for games against Chelsea, Manchester City, Crystal Palace and Arsenal, United manager Louis van Gaal opted to delay his return to the first team.
An injury to Angel Di Maria paved the way for his return in the 3-0 win over Hull City on Saturday 29 November and the former Athletic Bilbao star retained his place in the first team for the visit of Hughes' side.
United skipper Wayne Rooney missed Tuesday's win, the club's fourth consecutive victory, and will undergo a scan on a knee injury on Wednesday 3 December. Van Gaal will be hopeful he is fit for the visit to Southampton on Monday 8 December.
The manager said: "My opinion is it not so heavy [serious] but I am not a doctor. So we have to wait for the scan then we will know more. But I hope it is not so heavy."
The club are also awaiting news on Di Maria's problem. The Argentine international's wife, Jorgelina Cardoso, told fans on Instagram the midfielder has suffered a small tear to his hamstring with United's manager suggesting the knock is likely to rule him out of the next game.
Van Gaal said: "Di Maria is not so heavy but of course he shall not play against Southampton. But you never know."
The United boss also revealed Daley Blind could return before the end of the year.