West Bromwich Albion boss Carlos Corberan expects Semi Ajayi to be out for around four months following surgery on a hamstring injury.

As well as Nigeria international Ajayi, Corberan has also lost fellow defenders Kyle Bartley and on-loan Paddy McNair.

McNair went off with a hamstring injury just four minutes into Saturday’s 0-0 home Championship draw with Cardiff City and is now expected to be out for eight weeks, while vice-captain Bartley will miss between four and six weeks with a knee problem.

Summer signing Torbjorn Heggem, who was brought in primarily as a centre-back, has so far been used at left-back.

But he shuffled across to deputise for McNair in the centre of defence against Cardiff and is expected to remain there for Friday night’s trip to Luton as faltering Albion look to end their winless run – now up to six matches – against the struggling Hatters.

“We’re talking about three specific centre-backs who have had injuries at the same time, all within a week,” Corberan told BBC Radio WM. “It will be a challenge for us.”

To add to Corberan’s injury woes, USA international striker Daryl Dike has had his return pushed back to next year after sustaining a muscle injury, having been out since February with an Achilles tendon problem.