Buccaneers general manager Mark Dominik confirmed Thursday that Nicks has an infected blister on the side of his left foot and Tynes has an infected toe on his right foot.
MRSA is a staph infection that is resistant to some antibiotics.
The cases were diagnosed last week while the Bucs were in New England holding joint practices with the Patriots before a preseason game.
The team hired a company to sanitize One Buc Place, the team's training facility, last week. A second cleaning has been scheduled as a precaution.
"Our primary concern is always the health and safety of our players and staff," Dominik said in a brief statement issued by the team. "Our players were informed of the situation and we sought the advice of experts, including the NFL's medical advisor, who provided counsel and approved of our comprehensive measures including the treatment of our practice facility."
The entire roster was informed of the infections Monday.
The Bucs said they don't know where Nicks and Tynes, who did not travel to New England, were exposed to MRSA. Both players are responding to treatment, and the club said no other MRSA infections have been discovered among teammates.
Nicks, an All Pro two years ago with the New Orleans Saints, has been recovering from surgery on his left big toe and has not played this preseason. He made the trip to New England, practiced, but did not play in the game.
Tynes, who helped the New York Giants win a pair of Super Bowls, signed with the Bucs before training camp, but has been sidelined the entire preseason by an ingrown toenail on his kicking foot.