Theus' withdrawal, first reported by the Los Angeles Times, came two days after he interviewed on campus with athletic director Mike Garrett.
Theus said that his interview with Garrett went very well, but he was going to pursue other opportunities. Theus said he was told he wasn't going to get the job.
Theus also said he was told that at least one of the assistants would need to be retained from Tim Floyd's former staff. Floyd's assistants -- Phil Johnson, Gib Arnold and Bob Cantu -- have continued to work on campus but haven't been told of their coaching fate.
Earlier this week, on multiple occasions, USC was rebuffed by Pitt coach Jamie Dixon for the job, which opened up when Tim Floyd resigned. Dixon was and remains USC's top target, but he has told the Trojans he's staying at Pitt, as his family has no interest in moving from Pittsburgh to Los Angeles.
Garrett, through an intermediary, inquired whether former NBA coach Jeff Van Gundy had any interest in the job, but to no avail. It's expected the same will be done regarding former NBA coach P.J. Carlesimo -- and he isn't likely to pursue the job, either.
According to a source, USC also was doing background checks on Utah coach Jim Boylen, also a former NBA assistant.
Cal State Northridge's Bobby Braswell remains a possible fallback candidate, what with his strong ties to the school and the area, and his success in making the Matadors relevant atop the Big West with a 2009 NCAA tournament berth.
The Times reported that former Arizona interim coach and Memphis Grizzlies assistant Kevin O'Neill could be in play for the job, too.
Andy Katz is a senior college basketball writer for ESPN.com.