MIAMI (Reuters) - The Miami Dolphins have signed infamous former St. Louis Rams and Buffalo Bills guard Richie Incognito, the team said on Wednesday.

Incognito, voted the dirtiest player in the NFL, was fined $50,000 in December after head-butting an opponent after the completion of a play.

After his sixth unnecessary roughness charge of the season, the Rams released him and he was picked up from waivers by the Bills.

He was originally selected by St. Louis in the third round (81st overall) of the 2005 NFL draft.

(Reporting by Simon Evans in Miami; editing by Ed Osmond)