This fall on CBS's Without a Trace: A Chicago doc vanishes, and Anthony LaPaglia and Co. are the prime suspects!

Don't laugh; it could happen. A rep for rival drama ER confirms that Dr. John Carter will be MIA for several weeks this fall to accommodate portrayer Noah Wyle's request for some time off. "He will be in the first two episodes," says the spokesperson, "and then there will be [an] absence."

According to Wyle's camp, the actor — who is entering his 10th season as the increasingly moody M.D. — expressed a desire to spend more time with his family, including wife Tracy and their 9-month-old son, Owen. "That's something he has discussed with the producers for some time," says his publicist, Eddie Michaels. "[But] he's not leaving."

Nonetheless, given the gains that Without a Trace has made in the ratings this summer opposite ER, Wyle's disappearing act — which sources say could last through November — couldn't have come at a worse time for NBC's long-running hospital saga. "[Wyle is] very much a part of the show this year," argues exec producer Scott Gemmill, who wouldn't confirm gossip that Carter will head to Africa in search of colleague Luca (Goran Visnjic) — and then stay put. "We have a big cast... and it's not like he's gone away for forever." Just in case, better keep George Clooney on speed-dial. — Additional reporting by Ileane Rudolph