Jazz inspires an avid gamesmanship among its practitioners and fans: the cognoscenti all but foam at the mouth at the prospect of finding the “next big thing,” be it a tradition-shattering idiom or a flamboyant young soloist. Those on the lookout for the latter–who want the chance to say they “heard him when”–should take note of three upcoming appearances by New Orleans altoist Donald Harrison’s quintet. Not because of Harrison: though his puckering gumbo tone and thoughtful, boldly chromatic improvising still impress, his fling as a new star came about 15 years ago, when he and trumpeter Terence Blanchard replaced the Marsalis brothers in Art Blakey’s Jazz Messengers. This time around Harrison gets to play the role of mentor and advocate; the up-and-comer is his 17-year-old nephew, trumpeter Christian Scott, who’ll share the front line with him. I haven’t heard Scott play and he’s yet to record, but I’m willing to trust reports from reliable friends who’ve heard him at the last two New Orleans Jazz & Heritage festivals: as they tell it, Scott’s the real deal, polished and powerful enough to stir up the kind of interest that Blanchard and Nicholas Payton did in their teens. I’ve heard a couple other excellent young trumpeters in New Orleans who’ve attracted far less attention than Scott; if his higher profile means he’s got that much more talent, he should supply some serious fireworks. And in any case, Harrison deserves a listen, if only to see where his dogged musical curiosity has taken him. On his recordings of the last several years he’s revisited his roots, incorporating the percussive second-line melodies of a Mardi Gras parade and honing a style that weds rib-house soul with conservatory complexity; in live performance he rarely disappoints. Tuesday, December 12, 8 PM, Metropolis Performing Arts Centre, 111 W. Campbell, Arlington Heights; 847-577-2121. Wednesday, December 13, 8 PM, Bennett-Gordon Hall, Ravinia Festival, Green Bay and Lake Cook Rds., Highland Park; 847-266-5100. Thursday, December 14, 7:30 PM, DuSable Museum of African American History, 740 E. 56th Pl.; 773-947-0600.