Gaines had been starting in place of the injured Terrance Mitchell, but he arrived at practice Thursday complaining of concussion symptoms, according to Browns head coach Hue Jackson.
Jackson announced that Gaines will not play on Sunday and said T.J. Carrie, who had been playing nickel, will probably start at cornerback opposite Denzel Ward. The Browns will use Briean Boddy-Calhoun as the nickel defensive back.
The Browns are down two cornerbacks as they prepare to face one of the NFL's top-ranked passing offenses. The Bucs have 16 passing touchdowns compared to one rushing touchdown this season.
Tampa Bay quarterback Jameis Winston threw for 395 yards and four touchdowns in a loss to Atlanta on Sunday.
"We understand what the challenge is,'' said Jackson. "They have 16 touchdown passes. That's how they score. They're going to throw the football.''
The Browns were already down one starter. Linebacker Joe Schobert, the team's leading tackler, will miss Sunday's game and probably several more with a pulled hamstring.