Everton midfielder Marouane Fellaini is set to miss the rest of the season after being told he needs surgery on the ankle he damaged in the Merseyside derby.
The 22-year-old Belgian was substituted in the February 6 fixture after a crunching tackle with Liverpool's Sotirios Kyrgiakos, who was sent off.
Everton manager David Moyes believes Fellaini will be absent for around six months, meaning he could return for the start of next season.
Moyes said on www.evertonfc.com: "He's not good. He's going to have an operation. He's got a similar injury to Robin van Persie and it's probably going to keep him out for six months."
Arsenal striker Van Persie suffered ankle ligament damage in November, while on Holland duty, and has not yet returned to action.