The first domino has fallen in NFL free agency, as Mario Williams announced shortly after the 3 p.m. CST start that he'd take his first official visit with the Buffalo Bills Tuesday night, according to Adam Schefter.

There was speculation that the Texans were clearing cap space in order to make a run at keeping Williams, but this news seems to contradict the possibility that he'll stay in town. Will Williams sign there? It could be a better fit for him than the Texans, since he'd be moving back to a 4-3 look and be paired with Marcel Dareus to for a very potent defensive line up in Buffalo.

Very, very interesting, but probably bad news for the Texans.

For more information on the Texans as free agency approaches, check out our Texans Free Agency StoryStream here. For more informaiton on the NFL's free agency craziness, check out SB Nation's NFL site.