Jameis Winston looked at his fellow Pro Bowlers with a tinge of envy. It's not that he didn't believe he should be playing among the NFL's best in the game -- the Tampa Bay Buccaneers quarterback passed for 4,042 yards, the third-most by a rookie in league history -- but Winston took note of the physiques of some of his peers such as Russell Wilson and Julio Jones.

The 6-foot-4, Winston, who weighed in the "upper 240s," flew back to Tampa determined to elevate his game and transform his body. But he wasn't motivated purely by an aesthetic desire to improve his physique. The 22-year-old Winston was determined, just weeks after his first NFL season, to avoid the dreaded sophomore slump.

"I heard from around the league that most rookies that come in, if they have a great year, they don't have a plan for the offseason," Winston said. "I had never handled an actual offseason before."

As a former two-sport athlete at Florida State, Winston relied on baseball conditioning to keep him in shape year-round. He never truly learned how to train as a football player continuously.

A lighter Jameis Winston goes through a workout during the Buccaneers' OTAs on Tuesday. Tampa Bay Buccaneers

"I wanted to have a plan, and I didn't want there to be any excuse for any decline," Winston said.

But Winston didn't have a plan, and he faced a major obstacle in forming one. NFL rules prohibit coaches from working with players and in some cases limit how often they can even see players during the first phase of the offseason. So Winston had his agent reach out to a man who could teach him.

Tim Grover, who has worked with NBA greats Michael Jordan and Kobe Bryant, received a call in early February. Grover agreed to meet and establish a preliminary workout but under one condition: Winston would have to abide by strict guidelines and show improvement by Grover's next visit.

"I have to put my stamp on him," said Grover, who is very selective about the high-profile clients he trains. "When it's actually time to follow up on it, sometimes athletes don't do it. I wanted to make sure not only was he saying the right things but was doing them."

Grover was pleasantly surprised when he resumed workouts with Winston a month later.

"He's a special individual from a knowledge standpoint," Grover said. "He just didn't know it. He's gone so long on natural talent, he didn't know how to take care of his body, what to eat, what to drink or how to get his rest."

One of the first things Grover did was modify Winston's diet. Like everyone, Winston, who prefers salt over sweets, occasionally indulges his snack cravings. Winston's guilty pleasure is a bag of potato chips late at night.

"He's gone so long on natural talent, he didn't know how to take care of his body, what to eat, what to drink or how to get his rest." Tim Grover on Jameis Winston

"He's 22 years old; I'm not going to tell him you're not going to go out and eat only kale," Grover said. "Instead of eating a whole bag of potato chips, cut it down by a third. It's too difficult to give individual food plans, and it's better to change eating habits."

Winston not only heeded Grover's advice, he chose his favorite snack a little more carefully.

"I try to eat the healthier potato chips like Sun Chips and the kettle cooked chips," Winston said. "But instead of eating them for a snack at night, I just moved that up with lunch. That was very helpful -- eating at the right time of day."

Grover designed a dietary schedule for Winston, which included avoiding heavy meals late at night. At certain intervals in the day, Winston was instructed to eat the most calories.

"I gave him an easy way to measure portions," Grover said. "I never want to say you can't eat this."

His instructions to Winston were simple: At dinner, protein should be the largest thing on your plate, followed by vegetables and starches third. Right before working out, change the ratio.

Jameis Winston, throwing out the first pitch at a Rays game in March, has lost almost 20 pounds during the offseason. Kim Klement/USA TODAY

"It's about portion size and portion control," Grover said. "It gets very detrimental when you tell an athlete, 'You can't have this.' They're more likely to do it."

Said Winston: "The first day of us speaking, he talked to me about how I should eat more while the sun is up and eat less when the sun goes down. I started doing that. I started eating from about six o'clock in the morning to four o'clock in the afternoon, and then when the sun started going down, I kind of slowed things up."

The strategy was effective. Without depriving Winston of his favorite foods but rather modifying his eating schedule, Grover helped him drop 18 pounds since February. Grover would prefer Winston lose about five more pounds to reach a goal weight between 225 to 229 pounds.

Once Winston's diet was addressed, Grover moved on to the next part of the regimen. One week out of the month, the two worked out together twice a day, which has scaled back to once daily during OTAs.

The intensity of the first workouts with Grover came as a shock to the former Heisman Trophy and national championship winner.

"It was pretty tough," Winston said. "When I first got there, we didn't even talk for all that long."

Not long after their conversation ended, Grover thought the workout would as well.

"I didn't think he was going to last the whole workout my first time around, but he didn't quit," Grover said. "Even though he didn't look like he's in the best shape from a conditioning standpoint, he could run for days. He is a worker, he's a gym rat. He's constantly watching film."

That rigorous work ethic, combined with his natural bravado, left little doubt in Winston's mind he could complete training that first day.

"I could tell he was just eager to see how I would perform," Winston said. "When he put that football in my hand and we started working out, I think he knew how serious I was."

Winston set out to increase his flexibility, and the Bucs' coaching staff wanted him to quicken his drop backs. Grover spent a lot time on Winston's footwork to eliminate any negative steps. He also focused on how Winston stops and lands rather than how he runs and jumps, to develop the right kind of pivot points for Winston to change direction. And Grover focused on increasing the velocity of Winston's throws.

Winston and Bucs receiver Mike Evans worked through countless routes and were together on and off the field. Winston invited Evans over to his house several times this offseason to break down film before watching Golden State Warriors games.

"It's just crazy for a guy so young," Evans said of Winston. "It's amazing; I've never seen a work ethic like his yet."

Mike Evans, who has worked out with Jameis Winston during the offseason, is impressed with his quarterback's work ethic. Joe Robbins/Getty Images

Buccaneers quarterbacks coach Mike Bajakian said Winston returned from that first Pro Bowl appearance with a better understanding of what it means to be a professional after watching his peers.

"He said Russell's [Wilson] intensity was impressive. No taking a snap off, no relaxing at all. He said the same thing about Julio Jones," Bajakian said. "When you're around those guys and see how they work on a daily basis, you see what it takes to be a pro for a sustained period of time."

While Winston is capable of gaining yards on the ground and drew inspiration at the Pro Bowl from Wilson, one of the NFL's top dual-threat quarterbacks, don't expect a full transformation overnight in his game.

But Grover said all indications point to a dramatic improvement once they conclude training and the regular season starts in early September. He also credits Dave Kennedy and the rest of Tampa's training staff for their progress with Winston.

"My body feels much better. When you're working out consistently and staying in shape, you never have to get in shape. That's the biggest thing."

"Frankly, Jameis is real," Bajakian said. "In my experiences with him, when he says he's going to do something, he does it. You can take him at face value for sure. I trust what he says to me. During the whole draft process, he said the only thing I can do is earn people's trust by how I act and do. He understands the process that it takes.

"... To me, it looks like he's doing everything he needs to do."

For Winston, putting in the dedication so early in his career probably will prevent him from worrying about it down the road.

"My body feels much better," he said. "When you're working out consistently and staying in shape, you never have to get in shape. That's the biggest thing."