Derrick Williams is struggling once again with the quadricep injury that he had just returned from - and will see a specialist to determine how long he'll be out for.

The Irishman wasn’t in the squad to face Rotherham United on Wednesday night despite starting the defeats to Norwich City and Bristol City.

The game against his former club last week was his first appearance in five weeks since limping off against Middlesbrough in early November with a quadricep strain.

Daniel Ayala was therefore recalled to the starting line-up against the Millers, partnering Darragh Lenihan, as Rovers’ defensive options looked stretched once again.

They are already without their other left-sided centra defender Scott Wharton with an Achilles injury, while Williams adds his name to an unavailability list which also includes right back options Joe Rankin-Costello and Elliott Bennett.

But a set-back for Williams is a concern, particularly given Ayala has been short of football in 2020, and since joining Rovers in September, after suffering with a groin issue earlier in the season.

Mowbray opted for Williams over Ayala against the Canaries, despite both having started at Bristol City when Lenihan was suspended.

“It’s his quad. He said he played at Saturday on 80 per cent. He started training the other day and had to walk off, saying his quad was sore,” Mowbray explained of Williams’ absence.

“I was moaning to him about the second Norwich goal, where it bounced perfect for him to boot it back over the halfway line and clear it and he lobbed it to their midfield player.

“He said it was because his quad was ready to rip. He’s got a quadricep problem at the minute so he wasn’t in the squad.

“With Scotty Wharton unavailable it disrupts the balance of the team if we’re trying to build, it’s hard when you’re asking Daniel Ayala to play left-sided centre back and try and pick passes.

“It’s more difficult and less fluent so let’s see where we go on that.

“Daniel was hobbling towards the end of the game, but we’ll see what Saturday brings.”

Midfielder Jacob Davenport missed the Millers win through illness - but Tom Trybull shook off his bout off illness to be involved, coming on as a second half substitute.