The person spoke to The Associated Press on the condition of anonymity Monday because the Dolphins would not confirm the visit.
Last year Incognito conceded he had a reputation for being "a less than model citizen."
Twice last season with St. Louis, Incognito was benched in games after drawing two personal fouls. The Rams waived him after the second benching, and he started the final three games for Buffalo.
Incognito criticized the Rams' dwindling fan base in 2008, made an obscene gesture to a TV cameraman during practice and encouraged hecklers by cupping his hands to his ears while leaving the field after a loss.