Foster, who sustained a stress fracture to his right foot against Everton in August, is in the midst of a 12-week lay-off after the injury forced the 30-year-old to undergo surgery.
With England's first-choice shot-stopper Joe Hart lacking form, Foster will be hoping to place pressure on his Manchester City counterpart with the World Cup in Brazil just seven months away.
However, Myhill has deputised in the absence of Foster and registered his third clean sheet of the season in West Brom's 2-0 win over Crystal Palace.
McAuley has hailed the impact of the Wales international, saying in the Daily Mirror: "He's got a few clean sheets under his belt.
"If we keep winning games it will be difficult for anyone to get back into the team.
"It's not really my call but Boaz has been fantastic for us. He's made saves when he needed to. He's in possession at the moment and doing very well.
"He's a great goalkeeper and great to have around the place. He's full of life and has loads of experience which helps as well."
Foster is due to return at the end of November but England manager Roy Hodgson could face the prospect of having his top two goalkeepers on the bench after Costel Pantilimon replaced Hart in City's 7-0 victory against Norwich last weekend.