Last year a strong lineup of traditionally minded contemporary blues acts (and, somewhat curiously, the rock band Toad the Wet Sprocket) joined together for the Blues at the Crossroads tour, paying homage to the legendary bluesman Robert Johnson. The tour returns this year with a new lineup. This time it will be The Fabulous Thunderbirds, James Cotton, Jody Williams and Bob Margolin performing songs by blues greats Muddy Waters and Howlin’ Wolf. Blues-rocker JJ Grey was originally on the bill, too, but has since canceled. He’ll be replaced by multi-instrumentalist Tinsley Ellis.