Roberto Martinez expects to be without captain Phil Jagielka for "eight to nine weeks" after the central defender picked up a knee injury during Everton's defeat to Arsenal.
Jagielka limped off the pitch at the Emirates Stadium early in the second half on Saturday after sustaining the injury while attempting to clear the ball in the 2-1 Premier League defeat.
Martinez revealed the extent of the 33-year-old's injury when speaking ahead of Everton's League Cup clash with Norwich City, and the Spaniard was in a positive mood despite losing a key man.
"We had really good news yesterday," he said. "Because after the game we expected the worst – especially in the way the injury happened, rotating the knee could have been anything.
"We had the scan, the medial ligament is affected, as we expected, but that is an injury that is quite straightforward in that point of view but there is no other damage in the knee.
"So the other structures are very strong, and it is the least [damage] that it could be. So we're really looking forward to getting Phil into rehab and see how quickly we can get him back.
"At the moment we're going to make sure we take the right cause of treatment. I wouldn't expect anything longer than eight to nine weeks [out]."
