After a 15-month N.F.L. investigation into claims of sexual misconduct against Cleveland Browns quarterback Deshaun Watson, a decision on how or whether Watson will be disciplined under the league’s personal conduct policy is expected Monday.

Sue L. Robinson, the retired federal judge jointly appointed by the N.F.L. and the N.F.L. Players Association to oversee player discipline, notified both the league and the players union on Sunday morning that she would issue her ruling on Monday, according to two people with direct knowledge of Robinson’s communication. These people requested anonymity because Robinson has not discussed the process publicly.

More than two dozen women have accused Watson of engaging in sexually coercive and lewd behavior toward women he hired for massages from the fall of 2019 through March 2021, when he was a member of the Houston Texans. Twenty-four women filed civil lawsuits against Watson and 20 suits were settled in June. Watson denied the claims and grand juries in two Texas counties declined to charge Watson criminally.

Among the conduct prohibited by the league’s personal conduct policy are sex offenses, actions that endanger the safety and well-being of another person and anything that undermines the league’s integrity.

The Browns traded for Watson in March, after a first grand jury declined to charge him but before a second one did, and awarded him a five-year, $230 million fully guaranteed contract. The decision on Watson’s discipline has been widely anticipated, not only as a result of the Browns’ investment in him, but because the breadth of allegations against Watson set this apart from any other personal conduct case that has been considered by the league.

The league and Watson’s representatives could not negotiate a mutually agreed upon discipline, putting the initial decision in Robinson’s hands. She oversaw a three-day hearing in late June, during which the N.F.L. recommended that Watson be suspended indefinitely and required to wait at least a full season to reapply, while the union and Watson’s representatives argued against a lengthy ban. This was the N.F.L.’s first personal conduct case to be heard by a disciplinary officer instead of Commissioner Roger Goodell, a protocol established in the 2020 collective bargaining agreement.

The league and the players association would have three business days after Robinson’s ruling to submit a written appeal, which would be handled by Goodell or a person of his choosing. But the players union said in a statement on Sunday night — before Robinson issued her decision — that it would not appeal and called on the N.F.L. to let the ruling stand.

“Every player, owner, business partner and stakeholder deserves to know that our process is legitimate and will not be tarnished based on the whims of the League office,” the union said. “This is why, regardless of her decision, Deshaun and the N.F.L.P.A. will stand by her ruling and we call on the N.F.L. to do the same.”

The N.F.L. began its investigation of Watson in March 2021, when the first accusers’ lawsuits were filed. The league’s investigators, who do not have subpoena power, met with 10 of the women who filed lawsuits against Watson, contemporaneous witnesses to verify their accounts and other women who have worked with Watson.