Gary Deegan is set to be out of action for up to four months with a stress fracture in his ankle.
Deegan had been making slow but steady progress following an ankle ligament operation at the end of last season. He tore his ligaments during the game at Reading in April and rewired surgery to reattach the ligament to the bone.
Boothroyd was as disappointed at the news as Deegan, saying to the CT: "I am disappointed for Gary as I was looking forward to him getting a good pre-season like the rest of the lads, but we are looking at three or four months out. He will be desperate to get back and we will have to manage that, but he will be like having a new signing when he returns."