Tampa Bay selected Winston with the first pick in this year's draft out of Florida State and signed him to a four-year contract reportedly worth $25.35 million.
Winston indicated he hopes to drop eight pounds before the start of the season.
"Trying to lose some weight, try to get back skinny," Winston said, according to NFL.com. "Right now I'm 238 (pounds), I'm trying to be my redshirt freshman year (weight), about 230. I mean, learn that playbook too, man, you can never go wrong with that."
Over two seasons as the Seminoles' starter, Winston completed 66 percent of his passes for 7,964 yards with 65 touchdowns and 28 interceptions. He won the Heisman Trophy in 2013.
In February a photo surfaced of Winston that appeared to show the quarterback out of shape. In the photo, a chord is wrapped around Winston's waist while he performs a drill.
Winston's personal quarterbacks coach, George Whitfield, explained that Winston "always had a thing about pushing his stomach out."