Here in Los Angeles, as Grammy weekend revs up, the music biz is about to play musical chairs. I can tell you exclusively that Doug Morris is set to take over Sony Music on July 1st. Morris was the highly successful chief of Universal Music Group, but retired to make away for Lucien Grainge. At the same time, UMG’s LA Antonio Reid may or not continue running Island DefJam Records depending on the forward motion of his TV career. If he goes to “American Idol” as a judge, Reid, sources say, will stick at UMG. But if he goes to Simon Cowell’s “X Factor,” Reid will exit UMG and head to Sony where he could run the RCA/J/Arista group. “It’s all about waiting for Simon,” says my source. Whoever gets Reid will be lucky, frankly. Anyway, the reason the job at RCA is open is because Barry Weiss left to run Universal’s New York operation. Ironically, RCA/J’s popular A&R man Larry Jackson left a few months earlier and wound up at Universal’s Los Angeles campus. And this is complicated now because it is well known that Weiss forced Jackson out (more to come on this), and then left himself. Whew!