Joe Segal makes an unlikely Santa, but he's brought the city a Christmas present in the form of tenor saxist Johnny Griffin. The Little Giant is home for the holiday, and not a moment too soon--his several galvanic performances from last summer's jazz fest are just now beginning to fade from memory. At the age of 60, Griffin is a marvel: he still plays with the stops-out sound, the brash swagger at even slow tempos, and the spendthrift recklessness of ideas that mark the Chicago tenor tradition, and he hasn't lost a step on himself. There are those of Griffin's generation who turned to merely recycling their slickest stuff, each packaging his own style into a respectably ossified museum piece. Certainly Griffin has retained the riffs and patterns he once used to bust his way to the top of the bebop heap, but these are more than once-new phrases slung together like so much empty jargon; they constitute a living language, which he uses like a master elocutionist to tell modern, timeless stories. None of this should detract from the fact that Griffin likes to get down and dirty, can funk it up like nobody's business, and has been known to throw decorum completely out the window on appropriate occasions. Christmas Eve should qualify. Saturday, Joe Segal's Jazz Showcase, Blackstone Hotel, 636 S. Michigan; 427-4300.