Michael Keane has revealed that he suffered a hairline structure to his skull after he and Idrissa Gueye clashed heads against Bournemouth in August 25th.
The defender spoke about his concern when he received the news at Everton's training ground ahead of the Merseyside derby.
The Telegraph reports him saying: "When they first told me that, I was worried. The first ten days were pretty horrendous. I couldn't move without the room spinning. I was sat at home not doing anything, (any exposure to) light would make my head all fuzzy. I had to stay still.
"You have to rest for a certain time, you can't play for two weeks, can't head a ball, you have to stick to them guidelines. But also you go on what you feel and to be honest, after two weeks, I didn't feel I could head the ball. When I did try, I was a bit worried at first. I started with really small balls, just gently throwing them up."
He continued: "But I soon had everyone chucking balls at me and I'm heading them. Once you've done it a few times and it feels fine, you are good to go."
The 26-year-old returned to the side back in September against Arsenal after a month out and has cemented his place back in the starting lineup since. He initially showed commanding and strong performances, but as Everton have struggled late lately, so has he with a run of less than impressive displays.
These performances have left Marco Silva's men moving further away from a Europa League spot, which like fans of the Toffees, has left Keane frustrated - with the side needing to improve if they are to qualify for the European competition next season.