• Belgian sent for tests on right knee after injury in training • Extent of problem is not yet known, say Manchester City

Manchester City fear Kevin De Bruyne could be sidelined for up to three months after the midfielder sustained a knee injury in training on Wednesday morning.

The Belgium international was immediately sent for tests on suspected ligament damage but later appeared with his teammates in Manchester at the premiere of All or Nothing, a documentary about last season’s champions to be aired on Amazon Prime, on crutches and with his right knee heavily strapped.

City would not confirm the extent of the injury, although De Bruyne is set for more tests on Thursday amid concerns that he has torn the lateral ligament in his right knee – an injury that usually takes up to 12 weeks to recover from. “We do not know the severity of the situation yet, and until all the examinations are complete we cannot comment,” a spokesman said.

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De Bruyne started the first game of the season at Arsenal on the bench, coming on only as a late substitute to allow as much rest as possible after competing in the later stages of the World Cup. Even though Pep Guardiola has more squad depth than most, the midfielder’s absence caused comment and his creative input was missed, which is probably why he was sent on for the last half-hour.

City have players who can do a similar job, most notably David Silva and Ilkay Gündogan, though De Bruyne is the player who brings the best out of his teammates and an absence of more than a few weeks would adversely affect their title defence.

“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,” said the defender Kyle Walker. “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.”

So influential was De Bruyne in City’s title campaign last season that he would most likely have been voted player of the season but for Mohamed Salah’s remarkable run of goals and performances that helped to carry Liverpool into the Champions League final.

With the transfer window already closed, losing their most gifted and versatile attacking performer for any length of time would be a blow to Guardiola and his team, though even if it were still possible to bring in a replacement City would have struggled to identify a player of the requisite quality.