Patrick Dempsey is somewhere behind the hedges, waiting in the late-afternoon emptiness of the garden at the Chateau Marmont. Sitting slouched at a table, wearing black boots, dark jeans, and a brown plaid button-down shirt, the Grey’s Anatomy star wearily yes-yeses into his PDA and then disconnects with an apologetic smile. He looks whipped. He’s pale. There are dark circles under his green eyes. Even his Prince Charming mane—which he claims has a life of its own—looks tired. “Isn’t it great back here?” asks the actor, surveying his sparsely populated surroundings. “I like to be alone a lot. I like my privacy. The older I get, the more I want to be around fewer and fewer people.”

The waiter, a young Jeff Goldblum look-alike, glides over with the wine list. He recommends a red, returns, and pours a taste. Dempsey sips and makes an ew face. “You taste it,” he urges. The wine is suggestive of something used to sterilize surgical instruments. “It’s kind of harsh,” Dempsey says. “It finishes tangy. With a heavy wine you really need to decant.” Little Goldblum hurries back with a decanter. “It probably needs to breathe for an hour,” Dempsey says. “It needs to open up.”

Yesterday the actor drove the first leg of the Baja 1000, a legendary off-road race that rumbles across Mexico every November. When he returned to L.A. via helicopter this morning, he left his Hypersport team in the lead. “I’m still waiting for the car to come in,” he says, eyeing his BlackBerry. “Today we were running third, and then we had a big pileup. So I don’t know if we’ll finish third or fourth or where.”

The PDA rings. “This could be good,” he says excitedly. “How are we? Where are we? Did we cross the finish line? What mile marker are we? Call me when they cross the finish line.”

“I’d be down there right now if I didn’t have to come back to do Oprah today,” he says as he hangs up. “No offense to Oprah. Racing is something I really need in my life right now. The excitement of it calms me down, oddly enough. You’re in the car and you’re alone. It’s a complete escape from everything.”

It’s hard to imagine why an actor who spent most of his late twenties and thirties—his prime, really—languishing in oblivion would want to escape from a hugely popular TV show (for which he scored a Golden Globe nomination for the second straight year) and a subsequent flurry of film offers (he’s starring in the upcoming family fairy tale Enchanted and playing Hilary Swank’s husband in the Dangerous Minds–like Freedom Writers). But Dempsey, 41, is growing tired of playing doctor—even though he’s got three more seasons left in his six-year contract. “Things are going well, but I’m not satisfied,” he says. “I don’t think the character is going to change that much. Shonda Rhimes has created a great show. And I’m contributing to that and have benefited from that profoundly. And she’s benefited by being smart enough to cast me when no one else did. [It’s] been a great opportunity, but it’s not the end-all, be-all of where I want to go.” To keep him stimulated in the meantime, Rhimes has given Dempsey some healthy (and well-muscled) competition: the virile Dr. Mark Sloan (Dr. McSteamy), played by former Charmed heartthrob Eric Dane, 34. Is McDreamy feeling the heat?