Goalkeeper Foster withdrew from the England squad after sustaining a thumb injury in training and Dorrans has been ruled out of Scotland's Euro 2016 qualifier against Germany on Sunday due to a heel problem.
Albion head coach Irvine is optimistic that both players will be available for the clash with Roberto Martinez's side a week on Saturday.
"Graham is hoping that three or four days off it and it will settle down. There's not really an awful lot you can do to treat it because of what it is and where it is," Irvine told the club's official website.
"It's a bruise but it's not like a bruise somewhere you don't notice it unless it gets hit, it's a bruise you notice every time you take a step.
"I will be surprised if he has still got problems with that kind of injury by that time [when West Brom face Everton]. I would expect that would have settled down in time.
"Hopefully he will be back training the early part of next week.”
When asked about Foster's injury, Irvine said: "We are assessing Ben.
"He just got his thumb jarred. He went to catch the ball, secured it with his left hand but it then ricocheted off and hit down on the top of his thumb. That's exactly the movement he wouldn't have wanted.
"He will be assessed as far as that's concerned going forward.
"We don't feel there's a need to do anything drastic at this particular moment. We are hoping that when he's assessed again on Monday he will be fine.
"There isn't a lot of swelling there, there's not a lot of bleeding. We don't believe it's a major injury or a big problem."
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