Mario Williams visiting with Dolphins

The Miami Dolphins may have transition tagged defensive end Olivier Vernon, but they are not sitting back assuming their 2012 third-round pick will be in a Dolphins jersey in 2016. According to NFL Network's Ian Rapoport, the Dolphins are hosting free agent defensive end Mario Williams on Saturday, taking a look at the former Buffalo Bills' player who was released on March 1. Williams, having been released, is free to sign with a new team at any time.

Williams has spent the last four seasons with the Bills after starting his career with the Houston Texans as the team's first overall selection in the 2006 NFL Draft. In his career, Williams has 96 sacks, along with 386 tackles, 21 passes defensed, 16 forced fumbles, five fumble recoveries, and a touchdown. He has been named to the Pro Bowl four times, including two back-to-back trips in 2013 and 2014 with the Bills, as well as having been a 2014 First-Team All-Pro selection.

The 2015 season was a disappointment for Williams, who only recorded five sacks, tied for the second lowest in his career and the first time since 2011, when he only played in five games, that he did not break into double digits in sacks. Williams never seemed comfortable in Rex Ryan's defensive scheme last year, which made him a 3-4 outside linebacker rather than his normal 4-3 defensive end role, and will now be looking for a system in which he can return to form in 2016.

The Dolphins have to address their defense for 2016, where the team should spend a lot of effort to upgrade a unit that disappointed last year. Williams would give the team an insurance option for Vernon's possible movement in free agency this year. The Dolphins placed the $12.7 million transition tag on Vernon, but he is free to test the market and see if he can find a better deal. Miami will have the right to match any deal, but it would be more likely that Vernon is allowed to leave for a new club.

Miami also has to make decisions on the future of defensive ends Cameron Wake and Derrick Shelby. Wake, who is under contract through the 2016 season and is coming off an Achilles tear that shortened his 2015 season, is currently slated to count for $9.8 million against the salary cap. If the team were to release him, he would provide $8.4 million in salary cap space. The Dolphins have approached Wake about re-negotiating his contract, either with a pay cut or with additional years on the deal to move some of his base salary into a signing bonus, pro-rated across the life of the contract; Wake, however, has not agreed to any new contract.

Shelby will be a free agent this offseason, though the Dolphins would likely want to re-sign him. Shelby has been the primary reserve defensive end for the team, and moved into the starting lineup with Wake's injury. He finished the year with a career high 3.5 sacks, giving him 9.0 for his career. He also tallied 37 tackles with one interception, returned for a touchdown, four passes defensed and two forced fumbles.

If the Dolphins are serious about signing Williams, Miami might have to allow Shelby to leave in free agency, and may have to cut Wake to get the salary cap savings.

Williams should command interest on the free agent market this offseason. Miami is his first visit since being released.