Cephus announced the leave on Twitter on Saturday, saying that the Dane County District Attorney's office is preparing to issue "unspecified charges" against him and that he needs to focus on clearing his name.
"I have been wrongfully accused of unlawful conduct, and I am innocent of any allegations associated with this consensual relationship," Cephus wrote on Twitter.
Cephus, who last season finished second on the team with 501 receiving yards despite playing only nine games because of a knee injury, practiced with the team through Friday. He spoke with Wisconsin coach Paul Chryst about the situation Saturday, a team spokesman said. Cephus has kept both the school and the athletic department updated during the investigation, according to a source.
"I realize that I don't have the relationships and political pull that others may have here at the university or with the Dane County District Attorney's office, but I am going to fight to clear my name of these allegations," Cephus wrote.
Madison police chief Mike Koval issued this statement over the weekend regarding Cephus' tweets, saying, "MPD has recently been made aware that there is an individual on the UW Football Team making various statements through social media platforms. The MPD has conducted an investigation relative to the information that this individual has been sharing.
"In so far as this is an open investigation awaiting further decisions from the District Attorney's Office, MPD will not be commenting further out of respect for the rights of individuals who have not been charged and are entitled to full due process of the law."
If Cephus is charged with sexual assault or any violent crime, he will be suspended immediately "pending factual inquiry," according to Wisconsin's student-athlete discipline policy. The inquiry would begin immediately, and Cephus would remain on scholarship with access to both academic and training services and facilities.
A group that includes athletic director Barry Alvarez and others would determine any possible discipline for Cephus at the conclusion of the inquiry. Cephus has 34 career receptions for 595 yards and six touchdowns in 23 games (13 starts).