Nike Inc has suspended its endorsement of Houston Texans' Deshaun Watson following civil lawsuits accusing the NFL quarterback of sexual assault and inappropriate conduct, the sportswear giant said on Wednesday.

Twenty-two women have come forward and filed lawsuits against Watson, 25, who is also being investigated by the NFL for allegations they described as "deeply disturbing".

"We are deeply concerned by the disturbing allegations and have suspended Deshaun Watson. We will continue to closely monitor the situation," Nike said in a statement.

Massage therapist Ashley Solis, the woman who filed the first lawsuit alleging sexual assault by Watson, disclosed her identity and said on Tuesday she has since experienced anxiety, depression and panic attacks.

"We were all deceived into thinking Deshaun Watson was a good guy and unfortunately we know that good guys can do terrible things," she had said.

In the lawsuits, Watson is accused of exposing his genitals to the women and forcing at least one to perform oral sex, accusations he has denied.

The Texans said in a letter to season ticket holders that they were taking the allegations seriously and would continue to monitor the situation.

"While we await the conclusion of these investigations, we express our strong stance against any form of sexual assault," the letter read.

"Our family and the entire Houston Texans organization are deeply troubled by any form of abuse and we condemn this type of behaviour."

The NFL said it had initiated an investigation under its Personal Conduct Policy.

Watson signed a four-year, $156 million contract extension with the Texans last September but requested a trade in January.

(Reporting by Nivedita Balu and Rohith Nair in Bengaluru; Editing by Christian Radnedge) ((;))