Each day that Alonzo Mourning spends riding an exercise bicycle rather than playing basketball forces the rapid development of Dikembe Mutombo to accelerate. For the Georgetown Hoyas, that is the upside to Mourning's month-old injury. But they must continually remind themselves that there are benefits because the sizable downside is about to become greater.

The Twin Towers Minus One alignment that the Hoyas have deployed since Mourning landed awkwardly after making a victory-preserving block Dec. 5 against Duke is more than sufficient for nights like Wednesday, when Mutombo conducted a 34-point dunkfest to lead a routine, 78-54 trouncing of overmatched Jackson State.

But with Seton Hall set to visit Capital Centre Saturday night and Mourning's return apparently not imminent, the 15th-ranked Hoyas (8-2) face the unnerving prospect of limping into the Big East Conference season with only two available regulars -- Mutombo and junior guard Ronny Thompson -- who have league experience.

They try to put on their all-is-well faces, pledging confidence in the ever-expanding abilities of Mutombo and their quickly maturing supporting cast of freshmen Joey Brown, Charles Harrison, Robert Churchwell and Lamont Morgan. But it's becoming more and more difficult: After junior Brian Kelly, Mourning's recent replacement, hurt his ankle Wednesday, Georgetown was left with six players who play regularly.

"The kids are certainly working hard, and I'm making demands of them and trying to get them to focus more for {Big East} competition," Thompson said. "Emotionally as well as physically, it reaches another level when you play league games, and a lot of the younger kids can't even perceive that.

"They were ready for Duke, so I think they're going to get themselves ready to play {Saturday}. Of course, we certainly would like to have Alonzo out there."

However, Thompson already has ruled out the possibility of the 6-foot-10 junior forward playing Saturday, and the task at hand is simply to get Mourning back to practice. He has been limited lately to trying to stay close to playing shape by running a treadmill and riding an exercise bike. Thompson insists there's no timetable for his return.

It has been a trial-and-error period for the Hoyas since Mourning capped perhaps his best game as a collegian by swatting away Brian Davis's driving attempt in the final moments of Georgetown's 79-74 victory over Duke. He strained the arch in his left foot on his landing, and missed five of the Hoyas' next six games.

Georgetown has tried virtually every recuperative strategy, from allowing Mourning short, controlled bursts of playing to letting him go full-bore to resting him completely. Each time he seemed healthy, he aggravated the injury.

Mourning missed games against Rice and St. Leo following the injury, then had 11 points and five rebounds in 28 minutes in a loss to Texas-El Paso three weeks ago. He practiced extensively last week and Thompson planned to use him sparingly Saturday against Houston, but Mourning landed badly after shooting a jump hook near the end of Friday's workout and was sidelined again.

Thompson said doctors once thought surgery might be necessary but have ruled that out. A bone scan was performed and no stress fracture was located.

"We just have to make the best out of it that we can," said Kelly, a junior college transfer from Cincinnati who has started the last three games and proved an effectively scrappy complement to Mutombo.

Kelly left the arena with a swollen ankle and on crutches Wednesday, but he said he didn't believe the injury to be more than a slight twist. Both he and Thompson seemed to think Kelly would be available for at least spot duty Saturday. "Brian has a tough tolerance for pain," Thompson said. "It would have to be kind of serious" for him not to play.

Of course, the Hoyas still have Mutombo. And he alone might be enough on many nights.

Thompson likes to describe his 7-2 senior center's basketball lifeline as being on an upward curve, and that slope has steepened in Mourning's absence. Mutombo has averaged 17.4 points, 12.8 rebounds and 6.2 blocks in five games without Mourning (compared to 13.2 points, 11.2 rebounds and 5.6 blocks in five contests alongside him). But even that statistical jump does not show the giant step his offensive game has taken.

Mutombo's low-post attacks still are fairly rudimentary -- he had six dunks and four layups among his 13 field goals (in 16 attempts) Wednesday -- but the polish is coming. Thompson is trying to get Mutombo to go around defenders as well as over them, and progress is evident. A spin to the left and finger-roll like Mutombo pulled off against Ohio State was not fathomable a year ago; the hook shots with either hand are becoming softer, the passes back to the perimeter more deft.

Mutombo still is quick to point out that his avenue to becoming an NBA lottery pick is with rebounding and defense, but he concedes: "With Alonzo not in there, I have to do more on offense. . . . I'm trying to work with the kids out there."

And Thompson, despite reminding that Mutombo still is "just a babe in the woods" in terms of basketball experience, revels in the advances. Mutombo arrived from Zaire four years ago unsure of his play. Now he's a certified star. "Dikembe has what you can't teach: heart," Thompson said.

So even under these trying circumstances, Thompson will not allow himself to appear rattled; if he must go to battle with just one of his towers, so be it. Asked whether his club is ready for the Big East, Thompson replied, "The question is whether . . . the Big East is ready for us."