Mario Williams visits Dolphins four days after release by Bills

— -- Free agent defensive end Mario Williams, who was released earlier this week by the Buffalo Bills, is visiting with the Miami Dolphins on Saturday, a source confirmed to ESPN's Josina Anderson.

Williams' planned visit to Miami was first reported Saturday by the NFL Network.

Long one of the NFL's top pass rushers, Williams had only five sacks last year for the Bills, who released him Tuesday.

The Dolphins are interested because they may lose defensive end Olivier Vernon in free agency, and the status of defensive end Cameron Wake also is uncertain.

Miami placed a $12.734 million transition tag on Vernon on Tuesday, allowing him to negotiate with other teams. The Dolphins have the right of first refusal to match any offer.

Wake is 34 and coming off a torn Achilles tendon, and the Dolphins have been negotiating to lower his $9.8 million salary cap hit.

Williams, 31, has 96 career sacks, but his production fell last year under new Bills coach Rex Ryan. At times, Williams complained about his role.

Williams, the first overall pick of the 2006 draft by the Houston Texans, is a four-time Pro Bowl selection -- earning trips with the Bills in both 2013 and 2014. Over his first three seasons with the Bills, 2012 through 2014, Williams made 38.0 sacks -- the fourth-most in the NFL over that span.

ESPN Bills reporter Mike Rodak and The Associated Press contributed to this report.