The defender is currently undergoing tests on a suspected ankle fracture and has not travelled with the rest of the squad to Newcastle for tomorrow’s Premier League fixture at St James’ Park.
Hayward said: “Unfortunately, Willy Boly sustained a serious injury to his left ankle in training earlier today.
“Initial tests show a fracture to his fibula, and he will undergo further imaging over the coming days to determine whether surgery is required or not.
“If surgery is required that will take place during the next week.”
Hayward also provided updates on a number of other injuries in the squad.
He said: “Ryan Bennett is recovering well from his adductor injury. He has now started outdoor rehab and he will return to training in the coming days.
“Pedro Neto has progressed well with his outdoor rehab this week and has trained with the squad ahead of tomorrow’s game against Newcastle.
“Bruno Jordao has trained for the last two days and is progressing well. We expect him to be fit for selection very soon.
“Finally, Meritan Shabani underwent surgery to repair his right ACL, which went very well with the surgeon very pleased with the outcome. He has now returned to Compton to begin his early stages of rehabilitation.”
