Manchester United have suffered a massive injury blow as star defender Eric Bailly is set to be out of action for at least a month after picking up a knee injury in his side's 4-0 defeat at the hands of Chelsea at Stamford Bridge on 23 October.

The 22-year-old, who moved to Old Trafford from Villarreal, has been a key player in the Red Devils' back four. However, Jose Mourinho replaced him with Marcos Rojo in the 52nd minute after Bailly suffered a serious knee injury against the Blues.

Mourinho confirmed the Ivory Coast international's injury looks bad and according to the Daily Record, Bailly is set to spend time on the sidelines, starting from United's EFL Cup clash against Manchester City on 26 October.

"He is injured and I am afraid he is badly injured. In his knee, in the ligament area. He feels it is really bad," United's official website quoted Mourinho as saying.

Bailly is set to undergo a full medical examination in Manchester to understand the extent of damage. However, initial examination suggests that the central defender has reportedly suffered injury to the lateral collateral ligament of the right knee.

The former La Liga defender's latest setback will be a massive blow for the ex-Real Madrid and Chelsea manager as he looks to help the 20-time English champions bounce back from the poor run. United have managed only one win in the league since the end of August and the Portuguese tactician will look to end his side's poor run in the league.

Eric Bailly
Eric Bailly was replaced for the first time in the Premier League against Chelsea Getty

Mourinho has the services of Chris Smalling, Daley Blind, Rojo and youngster Timothy Fosu-Mensah as the other options in the heart of the back four. Should the Dutchman play alongside Smalling, United manager then has star Luke Shaw in the left-back position.