Jesse Marsch reveals disappointing fresh setback for Leeds United leader after Brighton loss

Cooper sustained an Achillies issue in the summer off-season, running on a treadmill, and was unable to play in any of Leeds’ pre-season friendlies or the opening three games of the season.

He played 45 minutes in the Carabao Cup against the Tykes but was left out of the squad for the 1-0 defeat at Brighton due to his new injury.

“He picked up a little something in his calf,” said head coach Jesse Marsch.

"And so we just again decided to be a little bit safe.”

Marsch is keen to continue exercising caution over players coming back from injuries and admits to frustration when there are new set-backs.

“Trying to get the guys that have been injured, it'll be the same with Luke Ayling, it'll be the same with Junior Firpo, that when we get them back in that we can build up fitness and sharpness and everything in a way so that we don't have little setbacks,” he said.

"I always get really frustrated when we build a process and then it winds up leading to a small little injury that interrupts things. So yeah, obviously we're disappointed with that, but it's not bad.”

Both Ayling and Firpo are expected back in training this week having missed pre-season and the Whites’ start to the Premier League season. Mateusz Bogusz will also make a return to training soon, although the Polish youngster may yet head out on loan.

Stuart Dallas and young goalkeeper Dani van den Heuvel remain Leeds’ long-term absentees after surgery and a summer car crash respectively.