What can a successful basketball team do for an encore when its cast keeps changing so dramatically?

That's the dilemma for BYU Coach Roger Reid, who, after two years of taking teams that weren't supposed to do much to the NCAA Tournament, is making his own act tough to follow.Consider: Reid loses four starters (Shawn Bradley, Steve Schreiner, Scott Moon and Ken Roberts), including his top three scorers and the heart of his defense. Freshman forward Jeff Campbell is also mission-bound, leaving Reid with eight guys who averaged 29 combined points a game on a team that scored 73 points a game.

What he gets in their place is two freshmen, two returned missionaries, a redshirt freshman and a junior-college transfer (maybe two).

But is Reid dismayed at the prospect of again starting from scratch, or worried about living up to high expectations? No way. This is a challenge, and a guy who likes challenges.

"I'm glad we've got that kind of reputation (for overachieving)," he said. "But we just take each year one at a time. We take the players we have and give them our undivided attention, and the results have been good."

Next season, Reid may face his toughest test. His lone returning starter is Nathan Call, a 5-foot-11 point guard who was widely thought to be too slow and too poor a shooter as BYU stumbled through its preseason, committing double-figure turnovers in game after game.

But WAC coaches who licked their chops over the prospect of having their quicker guards face Call frequently complimented him in post-game interviews, recognizing that Call did a solid job of quarterbacking the Cougar offense. Call's 164 assists topped Danny Ainge's BYU record of 158, and while he shot just 38 percent from the field, he improved as the season progressed, hitting 41 percent in WAC play and 50 percent in two NCAA games.

And Call is the only player that Reid is willing to name as a starter at this point. "Nate Call is the starter until someone beats him out," the coach said.

Other likely candidates for starting roles are Gary Trost, Mark Heslop and Jared Miller. Trost seems like a lock, based on his sometimes-spectacular play off the bench this season, but Reid said he would like to see Trost put on more muscle. Heslop is a good shooter and was a starter at the beginning of this past season, but he was beaten out by Moon for defensive and ballhandling reasons. And Miller, who will be a junior, led the team in rebounds per minute and showed some good offensive moves but also was the runaway leader in fouls per minute.

Of the other four returnees, only Mark Santiago, a dependable backup point guard, would appear to figure prominently in BYU's plans. Keegan Kane, a 6-5 shooting guard; Robert Jones, a 6-6 forward; and David Astle, a 6-9 forward-center, all need to show improvement, Reid said.

And that brings us to the newcomers. Perhaps the best prospect for immediate help is 6-9, 230-pound forward Kevin Nixon from Utah Valley Community College. The leading scorer at UVCC, Nixon played his freshman season at Northwestern, where he made the All-Big 10 freshman team.

"Kevin can play inside or outside and can shoot from anywhere on the floor," said UVCC Coach Duke Reid. "He has all the moves to free himself with or without the ball."

The redshirt freshman is Shane Knight, a slim (185 pounds), 6-8 forward who was sought by several Pac-10 and WAC schools out of Mount Carmel High in San Diego. "He's an excellent shooter, and he can shoot outside," said Reid. "He'll give us a dimension from the wing position that we didn't have this year."

Now come the real question marks - the players returning from missions and the new-recruit freshmen. Reid is reluctant to say much about them until he sees them practice.

Of freshmen, in particular, he said, "There's no way you can tell if they are going to be able to play right away. Some of them turn out to be good, some of them turn out to be flops."

Anyway, for the record, the mission returnees are Russell Larson, a 6-10 center from Clearfield who went into the mission field right out of high school, and John Fish, a 6-8 forward who played a freshman season at BYU before his mission. The true freshmen, meanwhile, are 6-7 Justin Weidauer of Cottonwood High, considered by some to be the top recruit in the state, this year, and 6-4 guard Craig Wilcox of Eastman, Ga. A third freshman signee, 6-7 Grant Berges of Phoenixville, Pa., will serve a mission first.

And, finally, there is the mystery player, as yet unsigned. Reid has one scholarship left to award and says he is looking for a guard with quickness and good defensive ability. Before last season Reid thought he had such a guard in Marc Thompson, a top Philadelphia prep who played junior college ball for Hobbs, N.M., JC. But Thompson ran into academic problems, which he has since apparently worked out. Reid said BYU is still interested in him, but so, reportedly, is are New Mexico and New Mexico State.

Stay tuned.