The 29-year-old made himself unavailable for international selection in May 2011 due to a series of injury problems and family considerations, but said at the time that he was "certainly not closing a door on the international side forever".
Foster is in now contention for a recall to the England squad for next month's World Cup qualifiers in San Marino and Montenegro.
England boss Roy Hodgson, who signed Foster on a loan deal that later became permanent while manager at the Hawthorns in the summer of 2011, failed in his bid to tempt the goalkeeper out of exile for Euro 2012.
But Hodgson received a more positive response when he recently renewed his offer.
Clarke said: "I had an informal chat with Ben last week when he said he might make himself available again for international selection which is good. It's Ben's choice.
"We sat here before and I've said the opposite, that it is great he spends time with his family.
"One of the reasons he told me is that the kids are a little bit older and are at school so that side has moved on a bit.
"His injury situation is much better and he has also got a burning ambition to play for his country in a major tournament. The World Cup next year in Brazil is a major tournament.
"He has been in excellent form this season either side of a couple of injuries he picked up."
Foster would provide experienced competition for current England number one Joe Hart, whose form has been under the spotlight in recent weeks after some high-profile errors for Manchester City.
Clarke said: "Competition for places is great. Hart impressed against Chelsea last week and Ben has been in good form. That competition can only be good for Roy Hodgson and England."
Hodgson is short of competition for Hart with Norwich's John Ruddy injured, and elected to name just one back-up keeper - Stoke's Jack Butland - in his squad to play Brazil earlier this month.
Foster, Albion's player of the year last season, has again been in outstanding form in their push for a Europa League spot after signing a new five-year contract in the summer.
He described his performance in the 2-0 win at Liverpool earlier this month - highlighted by a penalty save from England captain Steve Gerrard - as the best of his career.
If he is recalled, Foster will be reunited with goalkeeping coach Dave Watson, with whom he worked while at Birmingham.
Meanwhile, England have revealed they will stay at a luxurious hotel on Copacabana Beach for their friendly clash with Brazil on June 2. It is their intention to use the same hotel as their World Cup base 12 months later, assuming they qualify.
The location will be a contrast to the remote Rustenberg base used for the 2010 World Cup in South Africa.
England opted for a base in the centre of Krakow for last summer's European Championship in Poland and Ukraine.