"Me and Coach Koetter have a great relationship," Winston told reporters. "It doesn't matter what anyone else can possibly say. Obviously a lot of stuff can come out when we're not doing as expected, but that's false."
NFL Network's Ian Rapoport said tension between Winston and Koetter was brewing over the direction of the offense and the team's handling of the quarterback's shoulder injury.
"Winston didn't feel fully supported as it relates to his injury. People didn't really know what he was playing through and how that contributed to his performance," Rapoport said Sunday.
Winston missed three games with a lingering shoulder injury before returning last week. He threw for 285 yards and two touchdowns against two interceptions Sunday, nearly leading the Bucs to a come-from-behind victory over Detroit.
Koetter is in his second year as the Bucs coach after taking over in 2016. Tampa went 9-7 last season and was considered a contender for the NFC South coming into 2017. The loss dropped the Bucs to 4-9, and they've lost Winston's last seven starts.
Ryan Fitzpatrick went 2-1 while filling in for Winston as the Bucs starter.