Since signing for Chelsea for a fee of £52m from RB Leipzig, Christopher Nkunku has barely stayed fit.

The £52 million signing has made just nine appearances in his first season at Stamford Bridge, mainly due to a knee injury which he suffered last summer which ruled him out of the first four months of the campaign.

Mauricio Pochettino has now confirmed that Nkunku has suffered another injury setback and could be out for up to a month.

Nkunku came on as a substitute in the second half of Chelsea’s Carabao Cup final against Liverpool on Sunday.

Surprisingly, Pochettino has said they don’t know when Nkunku picked up the injury.

“We got yesterday [on Monday] that Nkunku was injured, we don’t know when he got injured,” Pochettino said.

“We need to see and evaluate every day but I think, at the moment, maybe three or four weeks out.

“Hope three or four weeks, no more.”

The injury means Nkunku will miss Chelsea’s FA Cup fifth-round tie against Leeds United on Wednesday evening.