He received several minutes of treatment before being allowed to return to action.
Awoniyi played on despite being in visible discomfort as Forest, chasing Champions League qualification, had used all their substitutes.
The extent of Awoniyi’s injury was discovered on Monday by the club’s medical staff and he was rushed to hospital for the operation.
Forest had said on Tuesday afternoon that Awoniyi was “recovering well”.
Forest owner Evangelos Marinakis appeared to engage in a heated exchange with boss Nuno Espirito Santo on the City Ground pitch immediately after Sunday’s game.
After criticism of the Greek’s behaviour, Forest said on Tuesday that the incident was because of Marinakis’ frustration that Awoniyi had continued to play after suffering the injury.
“At Nottingham Forest, this principle is not just policy for us; it is the deeply held belief and conviction of our owner,” the club said in a statement.
“To Evangelos Marinakis, this isn’t just a football club – it’s family – and he instils that message in all of us.
“That is why he was so personally and emotionally invested in the situation that unfolded at the City Ground on Sunday.
“His reaction was one of deep care, responsibility, and emotional investment in one of our own.
“In moments like that he demonstrates his leadership, not just through words, but through action and presence.
“In the final 10 minutes of the game, when he saw our player clearly in discomfort, struggling through visible pain, it became increasingly difficult for him to stay on the sidelines.
“His deep frustration at seeing our player lying on the ground in severe pain – something no one with genuine care could ignore – triggered him to go onto the pitch.
“It was instinctive, human, and a reflection of just how much this team and its people mean to him. He would do the same again if such an unfortunate event were ever to reoccur.”
