Guitarist Phillip Walker’s music resides in a challenging middle territory. With his high-energy approach and love for up-tempo variations on traditional blues, he’s got one foot in the modernist camp. On the other hand, his smooth, string-bending leads are fired out with tough-toned aggression, and supported by a hard shuffle that easily recalls the musicians who were his idols when he was growing up in Louisiana and Texas–B.B. King, the young Lonnie Brooks (then known as Guitar Junior), and regional legend Lonesome Sundown. Walker sometimes sounds as if he’s trying to force himself into the pop-blues mold of Robert Cray–a recent LP includes a version of “Don’t Be Afraid of the Dark”–but he’s at his best when he sticks to his roots. Walker’s singing has been compared to early Ray Charles; that’s a bit overstated, but his voice is more than adequate to do justice to the emotional range of his music, especially the ballads he intersperses among the celebratory flag-wavers and raunchy blues standards. Tonight and Saturday, Rosa’s, 3420 W. Armitage; 342-0452.