Two years after Cleveland Browns quarterback Deshaun Watson settled 23 lawsuits filed by massage therapists who said he had turned massage appointments sexual without their consent, another woman has accused Watson of sexual assault and battery.

In a lawsuit filed Monday in Harris County, Texas, a woman said that Watson “aggressively” sexually assaulted her in October 2020, when he played for the Houston Texans. The woman, who is not a massage therapist, said he had forcibly penetrated her after she declined to massage his buttocks.

According to the lawsuit, Watson went to the woman’s apartment for what was supposed to be a dinner date and removed his clothes while she was in another room getting ready. He demanded that she massage his buttocks, according to the civil complaint, and when she did not, the complaint said, he positioned her on the bed next to him, partially undressed her and began to “roughly” penetrate her for several minutes.

The woman’s accusations of forcible penetration are among the most severe that have been leveled against Watson.

“This is an extremely serious matter,” said her lawyer, Tony Buzbee, who also represented 25 other women who previously brought sexual misconduct lawsuits against Watson. “We intend to pursue this case with the same aggressiveness with which we pursued the others. We want a jury trial.”

Watson’s lawyer, Rusty Hardin, did not respond to a request for comment, and a spokesman for the Browns declined to comment. Watson has previously said he has never assaulted anyone.

Two Texas grand juries declined to indict Watson on criminal charges in March 2022, the same month that the Browns traded for Watson and gave him a five-year, $230 million fully guaranteed contract. He still faces two other open civil lawsuits, filed in 2021 and 2022.

The woman who filed the latest lawsuit, which was reported earlier by ProFootballTalk, had not previously made any public accusations against Watson. Mr. Buzbee said he did not know if she would file a report with the police.

Watson was fined $5 million by the N.F.L. and suspended for 11 games in 2022 for violating the league’s personal conduct policy. Among the terms of his disciplinary settlement with the N.F.L. were that he would not be subject to any further punishment from the league for any other accusations arising from the “same or substantially similar conduct” that happened before the discipline was imposed. He could be investigated and further penalized, though, for any previous incident that involved the use or threat of physical force or that is charged criminally.

An N.F.L. spokesman said the league was “reviewing the complaint.”

Watson started at quarterback for the Browns on Sunday in a 33-17 season-opening loss to the Dallas Cowboys.