What's Up Docs?

Secrets?'' Noah Wyle stands beside the batting cage in Dodger Stadium. Before stepping in to take his cuts, he pauses, adjusts his Hollywood All-Stars uniform, and leans forward to confide a detail about coming episodes of ER: ''I think a lot of sick people are going to be on the show.''

Gee, thanks, Noah. Maybe George Clooney will be more helpful. During a break on the Barstow, Calif., set of the feature film From Dusk Till Dawn, he agrees to give a sneak preview: ''I think Noah and I become lovers on the show. Last season you could see the longing glances across the room.''

Before you file suit for plot malpractice, consider that all summer Wyle and Clooney have fielded as many questions as ER's docs have ordered CBC's and Chem 7's (stat!). And the actors are just as curious — and almost as in the dark — as everyone else about the return of ER, one of the fall's most highly anticipated TV events. In its first year of prime-time residency, the medical marvel ranked third for the season and received eight Emmys, including awards for writing and directing. ABC hopes to stop ER, or at least slow it down, by pitting Steven Bochco's innovative courtroom drama, Murder One, against it. But don't be surprised if Murder gets slaughtered and moved to a safer time slot, just as CBS transferred and resuscitated Chicago Hope last season after ER sent it reeling. (This fall the black-Eye network sticks with 48 Hours.)

''Murder One may take a little chunk out of us,'' admits Clooney. ''It's not that we're indestructible.'' But he agrees with Wyle, who says, ''Our biggest competition is our first season, not any other show.''

NBC Entertainment president Warren Littlefield, by contrast, boldly predicts that the show will see ''a sophomore surge'' as more viewers discover ER. ''It's a roller-coaster ride,'' he says, ''that goes from 100 miles per hour almost to a dead stop, and then starts back up again. You never know where you're going, but you have to be there.''

That ride can be exhausting for those who take it every day. Executive producer John Wells thinks his biggest challenge may be ''not having enough rest.'' Wells and his writers took off only two weeks between seasons — but they still haven't provided the actors with much of a map of what's ahead, which is typical. ''When we get the scripts,'' Wyle explains, ''we pore over them, trying to find good stuff to [figure out] who the hell we're playing. And there have been times that we're like, 'Oh, Lewis has a sister!' 'Oh, look at that, Dr. Greene's got a mom!' We were in episode 12 before George knew he had a son, episode 14 before I knew I had a brother — and they killed him by 17.''

Even so, the actors have learned — and are willing to divulge — a few of their characters' upcoming traumas. Take Dr. Ross. ''Last year I really got nailed,'' Clooney, 34, says merrily. ''Every single [media] story about Doug Ross was, he's an alcoholic womanizer.'' This season, Clooney and viewers alike will discover more about Ross' past and family (how did he wind up a pediatrician, anyway?). Not that he's finished with womanizing: Ross and Nurse Carol Hathaway (Julianna Margulies) continue to wrestle with their attraction to each other.