David Cornwell, who represents Alex Rodriguez and is a familiar foe of the NFL Players Association, was retained by Miami Dolphins offensive tackle Jonathan Martin.
He is expected to advise Martin and his family during the NFL investigation and related contractual and peripheral matters that could arise depending on the outcome of Martin's continued leave from the Dolphins.
Cornwell is a familiar name in sports and regularly represents athletes who have found their way into trouble.
Donte Stallworth and Ben Roethlisberger hired Cornwell in criminal cases. Rodriguez turned to Cornwell when he was suspended 211 games by Major League Baseball.
Cornwell previously worked for the NFL and was the ranking official responsible for monitoring and reviewing minority hiring. He was a close associate of then-public relations spokesperson Roger Goodell, who is currently NFL commissioner.
Cornwell penned an extensive 11-page letter to agents in July 2012, ripping NFLPA executive director DeMaurice Smith for his version of negotiations during the lockout.
Their rocky relationship dates to 2008, when Cornwell was vying for the role Smith elevated to with the NFLPA following the death of Gene Upshaw. Cornwell directly blamed Smith for economic imbalance among players.
"Despite my greatest hopes, my personal experience reveals that (Smith's) vision in 2008 was little more than an inside Washington political campaign -- high on style, low on substance," Cornwell wrote in the memo, a copy of which was obtained. "(His) grandiose pronouncements did not translate into meaningful progress in the business of playing football. Rather than advancing the partnership between players and team owners, the new 10-year CBA relegated NFL players' status to mere employees."