BOULDER — Michael Sipili's short-term status became clearer Thursday, but the University of Colorado linebacker's future in the football program remains uncertain.

Sipili formally was charged with second-degree assault causing bodily injury and criminal mischief in Boulder County District Court.

Already suspended indefinitely by coach Dan Hawkins, Sipili is scheduled for a preliminary hearing Sept. 6, five days after CU opens the season against Colorado State at Invesco Field at Mile High.

Asked if the hearing date at least precludes him from playing against CSU, Hawkins said: "If nothing is resolved, that's right."

Hawkins has said his decision on Sipili's future will not be made until a legal resolution is rendered. But with the 6-foot-1, 250-pound sophomore sidelined for the opener, junior R.J. Brown is getting more work with the No. 1 defense.

Sipili, 19, was arrested Aug. 1 on suspicion of tackling and punching John Antrim, a 22-year-old CU student, in June.

According to a Boulder police report, Antrim required surgery for three facial fractures.

Sipili and attorney Lou Rubino would not comment Thursday, but Sipili expressed remorse about the incident shortly after CU started training camp. He said he "feels horrible" and believes he "let my team down."

Also serving suspensions for their parts in summer brawling incidents are defensive tackles Chris Perri (three games) and Taj Kaynor (one game). Perri, 20, was involved in the Sipili incident in June and fighting with Kaynor, 21, on July 4.

Linebackers coach Brian Cabral said Brown "to his credit, is stepping up. . . . If anything does happen with Sipili (to keep him out of the lineup), then R.J. is ready to go. He's earned that, and he's ready for it."

Brown, CU's special teams captain, said the two areas he needs to focus on as an inside linebacker are "quickness and seeing things a little faster. I'm starting to understand the defense and how it all comes together . . . but I need to react a little faster. I understand the defense better than I ever have before, know where I've got to be."

The 6-1, 230-pound Brown, a former walk-on, "just needs experience; he doesn't have any game experience (and) he needs that kind of confidence," Cabral said. "But he knows what he's doing and he works hard at it, so we don't worry about that."

On their return trip from San Antonio and the Big 12 Conference's preseason media briefing, Brown asked Hawkins why he had been put on scholarship.

Hawkins' response: "Because you're a tough guy, you're a hard worker, you're a good leader, you do things right, you're the kind of guy we want in the program. And you want to reward that."

"I love the guy, I really do," Hawkins said.

Depth remains Cabral's top concern. Freshman Nate Vaiomounga moved from safety to linebacker last week, but Cabral said there has been no talk of returning junior Maurice Cantrell to linebacker from fullback.

ETC.: Defensive tackle Curtis Cunningham, from Columbine High School, has become CU's sixth known 2008 commitment. . . . Redshirt candidates should be clearer after Saturday's scrimmage. About a dozen freshmen could contribute this season, with half that number in both lines. . . . Summer school grades have not been posted.

brooksb@RockyMountainNews.com or 303-954-5466. The Boulder Daily Camera contributed to this report.