Manchester United are reportedly concerned that Eric Bailly could not return to action from a knee injury until the turn of the year.
The Ivorian had to undergo surgery after suffering knee ligament damage since a pre-season meeting with Tottenham Hotspur in July.
Reports had initially stated that Bailly was ahead of schedule in his recovery process and would potentially return by November.
According to the Daily Mail, however, the 25-year-old is 'struggling' to recover from yet another knee problem, prompting the club to fear that he will not make a return to action until 2020.
The defender, who moved to United from Villarreal for £30m in 2016, has been blighted by various injury woes ever since moving to Old Trafford.
United's overall stability came into question once again after they threw away a lead to draw 1-1 with Arsenal at Old Trafford on Monday night.