Crystal Palace face a centre-back crisis at Chelsea on Sunday after new signing Chadi Riad suffered possible ligament damage.

The Moroccan was forced off with a knee injury just 10 minutes into Palace’s 4-0 Carabao Cup second-round win over Norwich on Tuesday, in which Eberechi Eze, Daichi Kamada and Jean-Philippe Mateta (twice) found the net.

Riad joined for £14million from Barcelona this summer.

Manager Oliver Glasner said: “It looks like something happened with the ligament in his knee. We all hope it was not too serious. It looks like to me he will at least miss the Chelsea game on Sunday.”

Glasner is left with just two fit centre-backs in Chris Richards and Rob Holding — though Nathaniel Clyne and Joel Ward can both operate on the right of a back three.

Joachim Andersen has departed to rejoin Fulham for £30m, and Marc Guehi’s future is approaching a conclusion, with Newcastle increasingly confident of prising him away from Selhurst Park.

Palace hope to sign two centre-backs before Friday’s 11pm deadline if Guehi is sold.

Goalkeeper Sam Johnstone was on the bench last night but has asked to leave Palace, with Wolves working on a deal to sign him. The England goalkeeper fell behind Dean Henderson as Palace’s No1 midway through last season and wants regular football.

The Eagles have namechecked Bournemouth’s Irish goalkeeper Mark Travers as a possible replacement for Johnstone. Bournemouth are set to sign Kepa Arrizabalaga on loan from Chelsea.