The 30-year-old, who joined the Toffees on loan from Manchester City, had been enjoying a positive spell on Merseyside before suffering the setback.
Grealish has now begun his recovery process and shared an update with fans on social media. Posting from his hospital bed on Instagram, the midfielder offered reassurance as he starts his rehabilitation journey following the operation.
"Didn’t want the season to end like this but that’s football, gutted. Surgery done and now all focus on getting back fit,” he wrote.
“I know for sure I will come back fitter, stronger and better than before. The support I’ve had since coming to this unbelievable club has meant the world to me.
“The staff, my teammates and especially the fans have been incredible and I absolutely love representing this club.
“I’ll be backing the lads all the way and doing everything I can to get back as soon as possible. Thank you again for all the love, it means so much. UTFT."