Tim Howard's chances of beating Neville Southall's Everton record for consecutive league appearances is under threat because of injury.
The American goalkeeper has made 210 Premier League appearances in a row for the club, a run stretching back to September 2007, when a finger injury forced him to miss two league games and he was replaced by German Stefan Wessels.
But manager David Moyes has revealed that Howard is struggling for fitness ahead of Saturday's home league game against Reading.
Howard, who will celebrate his 34th birthday next Wednesday, suffered a knock during Tuesday's 3-1 FA Cup fifth-round replay victory over Oldham – and that could yet deny him the chance to make Everton history.
He is just two games short of equalling Southall's club record of 212 consecutive league appearances, set between October 1987 and February 1993.
If Howard fails to make it, then Slovakia international Jan Mucha will finally make his Premier League debut - almost three years after moving to Goodison Park from Legia Warsaw.
"I've got a doubt about Tim Howard, the goalkeeper," Moyes said. "He took a knock in midweek. So I'll need to assess that one."
Striker Victor Anichebe is also a doubt to face Reading, having missed Everton's last two games with a knock, but midfielder Marouane Fellaini is likely to return after sitting out the midweek cup win over Oldham with a minor injury.
Moyes' concerns over the right-back position, though, have been eased by the return to fitness of Seamus Coleman after a month out with a thigh injury.
Coleman made his comeback last Saturday as Everton suffered a 2-1 league defeat at Norwich, and also came through the Oldham game on Wednesday.
That is a huge boost to Moyes, who could be without Tony Hibbert for the rest of the season because of a calf injury.
The manager said: "We missed Seamus badly for the month or so he was out. We missed him and Tony Hibbert as much as we missed anybody, because we had to go several weeks without a recognised right-back, and because of that, we had to juggle and change things around a bit."
Hibbert has made only five appearances this season, and none since the beginning of December. Asked if there was a chance of seeing him play again soon, Moyes said: "I'm not sure if we will. He might be back before the end of the season, with a bit of luck."