Foster hopes to be included in the England squad for the Word Cup in Brazil this summer, but is likely to be battling for an understudy role to Manchester City keeper Joe Hart.
Mel has been highly impressed with Foster, who has been on good form since spending the first half of the campaign on the sidelines with a foot injury.
"For me, Ben Foster is the best goalkeeper in England," said Mel. "In particular, he is very good with crosses. He has no problem dealing with them.
"For me, he should be England's number one at the World Cup, but Hart at City is a good goalkeeper, a good player.
"Obviously it's normal I say this about Ben because he is my player, but he is a very, very good goalkeeper."
Meanwhile, Mel plans to revive Craig Dawson's career at Albion, staring with Saturday's Premier League clash at Crystal Palace.
Dawson had fallen out of favour at The Hawthorns under previous boss Steve Clarke and spent some time on loan at Bolton Wanderers, but Mel reckons the centre-back has a big role to play for the team.
"He is the future of West Brom," said Mel. "He is a very good centre back, and he wants to play matches, which is normal.
"Now, it's better he stays here. For example, against Palace, we need him to play. Dawson is in the 11 for this game. He is ready, he wants to play, which is very good for us.
"He is Premier League quality, a strong centre back, and his mentality is very good."