Foster faces another six weeks on the sidelines with a fractured foot and has paid tribute to the performances of Myhill, who starred in the win at Old Trafford and last weekend's draw with Arsenal.
Foster told the club's official website: "He's been really good. I get to see him day in, day out in training so it's no surprise to me.
"It's the way football is, that if someone has the misfortune of being injured, then it's always going to be good fortune for someone else.
"It's up to that person to take the chance."