About a year and a half ago, Curtis Stigers released his first album as a jazz singer--and an awfully good one at that. But I'd guess that Baby Plays Around (Concord) took his old fans by surprise: After all, this is the same Curtis Stigers who hit the charts as a blue-eyed soul man back in 1991, rocketing into the top ten with "I Wonder Why." Two more tunes from his eponymously titled debut, "Never Saw a Miracle" and "You're All That Matters to Me," also entered the soft-pop pantheon; he went on to tour with the likes of Rod Stewart and Joe Cocker, and eventually landed a song on a Dawson's Creek sound track CD. But by that time, Stigers had returned to his first love--the mainstream jazz he played growing up in Boise, where he sat in, as a singer and tenor saxist, on sessions led by the redoubtable soul-jazz pianist Gene Harris. Stigers has a hale, rugged vocal timbre with marbled overtones, but in contrast to these rough edges, his phrasing and dynamics are silky smooth, which enables him to meet both the technical and emotional demands of jazz. His approach has something in common with Tony Bennett's, and at times you might hear the influence of Nat "King" Cole in Stigers's crisp, even delicate enunciation--in any case, his voice turns out to be even better suited to jazz than to pop. But Stigers retains an affection for well-penned pop ballads, and it's led him to some terrific material rarely interpreted by jazz singers: the title track to Baby Plays Around is by Elvis Costello, and this year's Secret Heart (also on Concord) takes its name from a Ron Sexsmith tune. Both songs express a longing that was the exclusive domain of jazz's torch singers until the 60s, when it became grist for the rock-pop mill; with his quiet, expressive renditions, Stigers helps reclaim that territory for a new generation of jazzers. He also handles fast tunes with conviction and aplomb, at tempos even faster than the originals; he scats a little too, drawing on his background as a saxist, and could do it even more without any complaints from me. This gig is his Chicago debut as a jazzman. Friday, August 16, 9 PM, and Saturday, August 17, 8 PM, Green Mill, 4802 N. Broadway; 773-878-5552.