As colleges struggle to control the public-relations damage caused by athletes’ criminal behavior, prominent conferences have begun measures to keep players with troubling pasts out of their teams’ nationally televised colors.

The Big 12 this week became the second major conference to move to bar incoming transfers who had been disciplined for “serious misconduct” at their previous universities. The rule, unanimously recommended by Big 12 athletic directors, is modeled on one adopted in May by the Southeastern Conference, and it reflects a rising awareness of the issue of sexual violence by athletes on campus.

The Big 12’s discussion of the rule was framed in part by the case of Sam Ukwuachu, a defensive lineman who transferred to Baylor, a member of the Big 12, in 2013. Ukwuachu was convicted Friday of sexually assaulting another Baylor athlete. Ukwuachu, who never played for Baylor, was sentenced to six months in jail and 10 years of probation. During the trial, a former girlfriend testified that he had assaulted her several years earlier, when he was a player at Boise State.

The Dallas Morning News first reported the Big 12 athletic directors’ vote Tuesday, with Commissioner Bob Bowlsby saying the rule on incoming transfers, though not final, would “cast a broad net in terms of making sure we perform due diligence on anyone we bring to campus.”

The SEC rule, on which the Big 12’s will be modeled, bars teams from accepting transfers if, at their previous universities, they were “subject to official university or athletics department disciplinary action” — not including suspensions that were levied pending investigations — for what it labeled “serious misconduct,” defined as “sexual assault, domestic violence or other forms of sexual violence.”

Greg Sankey, the SEC commissioner, said, “Our universities and the conference have taken the position that we don’t want to create situations or reputational harm by accepting transfers who have significant conduct issues in their past.”

He added: “We’ve talked about our leadership position as a conference — our universities, our athletic successes, the attention paid. Our leadership clearly thought this was the appropriate policy, and that it certainly sets an example others might follow.”

But critics said such rules, if approved only by certain conferences, would create an inconsistent patchwork in a college sports environment in which coaches are under constant pressure to recruit top talent. Alabama Coach Nick Saban told in June that he wished the five major football conferences, which enjoy substantial governing autonomy at the N.C.A.A., had one consistent rule. Though a Division I-wide rule could be passed at the N.C.A.A. convention in January, transfer policy is not yet an area of autonomy.

The other three major football conferences — the Big Ten, the Pacific-12 and the Atlantic Coast Conference — have not discussed conferencewide policies on transfers with legal issues, according to representatives of each league, though a discussion of the topic in the Big Ten is likely.

Even a more broadly applied rule would leave a worrisome loophole because the new regulations apply only to incoming transfers. Institutions in most conferences still have wide discretion to decide whether one of their own athletes disciplined for serious misconduct may return to the field.

For example, at Oklahoma, of the Big 12, running back Joe Mixon has returned to the team after an allegation that he punched a woman in the face last year. Mixon accepted a misdemeanor charge without acknowledging guilt and was disciplined with a season-long suspension. And at Louisiana State, of the SEC, offensive lineman Jevonte Domond was reinstated this month after being suspended in May after an arrest on charges that he had assaulted his girlfriend. Those charges are pending.

“Our institutions already all have student disciplinary processes and even athletic department processes, and there has been an historical respect for the institutional policies being the priority,” said Sankey, who noted that in cases in which an athlete was already a student at an institution, the college had “clearer information,” and “there is information known directly.”

Nancy Hogshead-Makar, senior director of advocacy at the Women’s Sports Foundation, said men with violent pasts should be allowed to transfer only if a university did something to thwart the risk posed to women on campus, so that “the risk of harm to women isn’t just shifted from one campus to another campus.”

Referring to the obligations that Title IX imposes on institutions of higher education, she added, “Federal law requires that if they know about a risk of harm, they have to take care of it.”

Baylor’s president, Kenneth W. Starr, has announced that the university’s faculty athletics representative, a former prosecutor, will conduct an internal probe into the Ukwuachu case. But from what is publicly known about his situation, it is not clear that a rule akin to the one proposed Tuesday would have barred his transfer to Baylor.

Ukwuachu, a defensive end from Pearland, Tex., started at Boise State as a redshirt freshman in 2012 before returning home to enroll at Baylor. He never played for the Bears; he was ineligible for the 2013 season because of transfer rules, and he missed the 2014 season, according to a Baylor coach, as he worked through “some issues.” In fact, he had been charged that June with sexually assaulting a Baylor women’s soccer player.

Last week, several news outlets highlighted his case, noting that Ukwuachu had been indicted more than a year ago and reporting that while he was at Boise State, his girlfriend at the time had reported emotional volatility and violence, including his punching a window. At trial last week, the former girlfriend testified that Ukwuachu had hit and choked her, according to The Associated Press.

That prompted a public back-and-forth of what was known about Ukwuachu’s behavior between Baylor and its coach, Art Briles, and Boise State and its former coach, Chris Petersen, who is now the coach at Washington.

On Friday, after Briles denied knowledge of accusations of violence made against Ukwuachu at Boise State, Petersen said in a statement that he had “thoroughly apprised” Briles of Ukwuachu’s “disciplinary record and dismissal.” Later that day, Baylor released a statement from Briles clarifying that in their conversation, Petersen “did not disclose that there had been violence toward women,” but rather that Ukwuachu had been involved in a “rocky relationship,” was “depressed,” and wished to be closer to home. Baylor also released a form signed by Boise State’s director of compliance indicating that Boise State had not “suspended or disqualified” Ukwuachu “for disciplinary reasons.”

Ultimately, Hogshead-Makar argued, the problem is a system of incentives in which highly competitive and well-compensated coaches and athletic department officials could be inclined to see a player’s talent as outweighing the threat he might pose to other students.

“When you think of the economics of college football, it only rewards one thing and it punishes brutally by not doing this thing — and that’s winning,” she said. “So the economics are not good for the risk of women.”

Photo by: Joe Jaszewski/The Idaho Statesman, via Associated Press

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