The defender sustained the fracture in training on Saturday, with the injury expected to keep him out of action for a number of months.
Hayward said: “Willy had surgery in London this morning to repair the bone with a small metal plate and screws.
“The procedure went as planned with no complications and he will now return to Compton to begin the early stages of his rehabilitation.
“Willy will be in a boot for the first six weeks, working hard to maintain fitness and muscle bulk in the leg before progressing to more functional activities.
“In terms of time scales, a lot depends on how he progresses in the first few weeks and how well the fracture heals.”