Manchester City are waiting to learn the extent of a serious knee injury suffered by key player Kevin De Bruyne in training.

Reports have suggested the Belgium playmaker could be out for two to four months after being hurt during a session on Wednesday.

The 27-year-old, who is due to undergo tests, arrived on crutches and wearing a leg brace as he attended the premiere of Amazon’s All Or Nothing fly-on-the-wall documentary about the club on Wednesday evening.

City have not yet indicated how long the player will be sidelined but a two-month lay-off would see him miss the opening Champions League fixtures and a potentially crucial clash against Liverpool on October 7.

A statement from the Premier League champions read: “Kevin De Bruyne is undergoing tests on his right knee after sustaining an injury at training on Wednesday.

“The extent of the problem is not yet known and we will bring you further updates on Kevin’s condition in due course.”

De Bruyne was outstanding during City's title success
De Bruyne was outstanding during City’s title triumph (Anthony Devlin/PA)

De Bruyne, one of the stars of last season’s title success, only returned to full training last week after a delayed summer break following the World Cup. He featured as a second-half substitute in the league campaign-opening win over Arsenal at the Emirates Stadium last Sunday.

The injury could be similar to one De Bruyne suffered during a game against Everton in 2016, when he was ruled out for nine weeks.

Speaking at the premiere in Manchester city centre, team-mate Kyle Walker said: “Kevin is a great player and it’s just unfortunate that it’s happened to him in training but there’s more than enough depth in the squad.

“We don’t just rely on one player. It’s a team game and whoever steps in will do well. Obviously it’s a big loss but we’ve got more than enough cover.”

City midfielder Ilkay Gundogan said of De Bruyne: “He played an incredible season.

“He had so much impact on our game. He was maybe the main man for us last season.

“He is very important. We all hope that it is not too serious so he can get back on the training field as soon as possible.”

City are next in action against Huddersfield at the Etihad Stadium on Sunday, their first home game of the campaign.

Gundogan said: “We couldn’t beat Huddersfield at the end of last season, so we are even more motivated. Hopefully we are going to get the three points.”