The Blues have lost loanee Joe Hart, who has returned to Manchester City, and McLeish is hoping Foster can emulate the form that his England team-mate showed at St Andrews in 2009/10.
The 27-year-old has collected four caps and started United's opening eight league games last season, but dropped to the bench once Edwin van der Sar returned from injury.
But McLeish believes that Foster will return to the England setup once he gets regular first team action under his belt with the Midlands club.
"We know that we've got a fantastic goalkeeper of great pedigree," McLeish told Sky Sports.
"Ben wants to get back in the England fold. Joe Hart knew that if he had a good season it would help with England. I spoke to Fabio Capello last year and he said the important thing for Joe was to get games.
"That's the same for Ben Foster. I totally agree with Capello's stance that Ben's not played enough games to be considered for the World Cup despite his great potential and despite the great goalkeeper he is.
"Ben will get games for Birmingham and hopefully he'll be competing for that No.1 spot."
McLeish added that he understands why Sir Alex Ferguson let Foster go after five years at Old Trafford and feels it was the right decision.
"I think Sir Alex knew it was time to let him go and spread his wings, that he couldn't hold him back anymore," he continued. "Sir Alex recognises it wasn't fair on the guy."
NEWS:Ferguson 'had to let Foster go'
Ferguson had earlier slammed Capello's decision to not include Foster in his travelling party to South Africa, but admitted that he had to let the gloveman depart Manchester United in order to further his career.
"Ben's the best England goalkeeper and I can't work out why he wasn't even considered simply because he didn't have enough football," he said.
“Ben's been a terrific servant for us, he's been very unlucky with a couple of injuries he's had with us last season and I think he deserves the opportunity to do better for himself."
By Owen Edwards
