FORT MYERS, Fla. -- Nobody knows what Pablo Sandoval's right-handed swing will look like this spring after the toll of shoulder surgery and a tedious nine-month rehabilitation.

But wait until you get a load of his right hook.

Last month, Sandoval walked into Ray Echevarria's makeshift gym in north Miami and signed up for boxing lessons. Having changed his dietary habits and exercise program as a way of getting leaner, the Kung Fu Panda decided it was time to get meaner, too.

And before anyone makes a crack about the notoriously portly Boston Red Sox third baseman being a heavyweight, know this: Sandoval's impulse to sting like a bee is another sign of how serious he appears to be about getting in shape to save his flagging career.

"I can not only sense that, I know it to be true," said Echevarria, a former U.S. Army veteran who owns Coach Ray's Boxing & Fitness. "From the previous seasons when Pablo came into spring training extremely overweight, he's really dedicated this time to his nutrition and his training to get where he's at right now. And he's in awesome shape, man."

Tomando lo mejor de cada deporte para estar al 💯 % y aportar siempre mi granito de arena en el equipo @miggy24 💪🏼⚾️️⛹🏽🚵🏽 🏆 #miguelcabrera @crboxingandfitness #2017goals #championship A post shared by Pablo Sandoval (@kfp48) on Jan 11, 2017 at 10:49am PST

It's a long-running joke that baseball players report to spring training every year and boast of being "in the best shape of my life." In Sandoval's case, it might be true, although that isn't saying much for someone whose belly grew so big that he snapped his belt buckle while taking a swing April 9 in Toronto.

For the record, Sandoval reported to Red Sox camp Thursday weighing "in the high 240s," according to Joe Ferrer, a certified strength and conditioning specialist at Bommarito Performance Systems in Miami, where Sandoval worked out five days a week for most of the winter. Josmir Romero, Sandoval's personal assistant, estimated the 30-year-old has dropped approximately 40 pounds since May, when he had surgery for a torn labrum in his left shoulder.

"He's like a new Panda," Romero said.

Sandoval's desire to control his weight seems earnest. But there are about 95 million reasons to be skeptical. His weight has fluctuated wildly since his big league debut with the San Francisco Giants in 2008, and he admitted to ESPN.com in December that he let himself go after signing a five-year, $95 million contract with the Red Sox following the 2014 season.

Even team officials are only cautiously optimistic that the fitter, trimmer Sandoval is here to stay. Red Sox president Dave Dombrowski says Sandoval "deserves tremendous credit for what he's done" but has not yet declared him the Opening Day third baseman, even though utility man Brock Holt is the only viable in-house alternative.

It's up to Sandoval, then, to convince everyone he can keep the weight off this time.

"I have to prove everything, especially when you're coming from an off year after the injuries," Sandoval said. "You have to prove a lot of things to the fans, to the team, to your teammates, to the sport."

Family pride

Shame can be a powerful motivator.

For seven years in San Francisco, Sandoval could have been a test case for Weight Watchers. The Giants put his girth front and center, making annual demands on him to slim down. They devised Operation Panda, a dietary and conditioning program, and tried to curb his overeating by limiting his ability to order room service on the road.

Sandoval would lose weight, but then gain it all back either by enjoying too much home cooking in Venezuela in the winter, or falling into bad habits during the season.

Regardless of his size, Sandoval had success. He was a two-time All-Star and the 2012 World Series MVP. He achieved a level of popularity in San Francisco that he need not buy a drink there -- even though his career earnings total $53 million and the Sox owe him $54.8 million more through 2020.

"He didn't tell me this, but just talking to him, it kind of seemed like after he won the three World Series and Boston signed him to a big deal, it's like maybe you lose a little motivation," Ferrer said. "That's just kind of how it felt to me."

Sandoval admitted as much, saying he got "so complacent with the things I already accomplished." And in two seasons with the Red Sox, he almost lost it all.

After ranking as one of the majors' worst every-day players in 2015, Sandoval lost his job last spring to upstart Travis Shaw, started just one of the season's first five games, and went 0-for-6 with four strikeouts. The exploding belt represented the depths of his humiliation.

Rock bottom wasn't far behind. Because neither he nor the Red Sox were able to pinpoint how he injured his shoulder, conspiracy theorists doubted whether he was really hurt, only grudgingly coming around when highly regarded orthopedic surgeon Dr. James Andrews confirmed the labrum tear. Sandoval's season ended May 3 on an operating table.

"I want to play eight more years to show my son, so he can see his dad play growing up. You learn a lot of things from the mistakes you make when you get comfortable. I've heard a lot. My family has helped me do it."

"It was tough for him," Romero said. "Not only for him, for everybody around him, because we're always looking to him, watching him play baseball. He took a lot from the situation about what he should do better, and that's what he became."

Sandoval also was dealing with personal issues. A dispute over his training program caused him to stop speaking with his older brother, Michael, and to leave longtime agent Gustavo Vasquez in favor of the Beverly Hills Sports Council. He got married for the second time last year and had a son -- "Baby Panda," Sandoval calls him -- who was born in May.

That was all the inspiration Papa Panda needed.

"I want to play eight more years to show my son, so he can see his dad play growing up," Sandoval said. "You learn a lot of things from the mistakes you make when you get comfortable. I've heard a lot. My family has helped me do it."

Putting in the work

Having watched Ferrer help Red Sox first baseman Hanley Ramirez overcome a 2015 shoulder injury and revive his career last season, Sandoval decided to enlist the strength and conditioning specialist to oversee his workouts.

The days began at 7:30 a.m., Ferrer said, with an hourlong "turf workout" to improve Sandoval's agility. After a series of core-strengthening exercises, they moved to the weight room, alternating upper- and lower-body lifts every other day.

"If you looked at him before, if you didn't know who he was, you wouldn't think he's an athlete. But if you see him now, you know he's an athlete." Ray Echevarria, Pablo Sandoval's boxing instructor

The Red Sox received frequent progress reports -- "Panda watch," if you will -- because Ferrer is close with Boston strength and conditioning coach Kiyoshi Momose.

Meanwhile, Sandoval put his new wife, Yulimar, in charge of his diet. She worked with a nutritionist to come up with healthier meals for Sandoval and cooked for him throughout the offseason.

"Part of [Sandoval's] issues in the past was not work ethic. It was other aspects of his life when we start talking about nutrition and those type of things," Dombrowski said. "This winter, I would say he was more committed to the total program."

Said Ferrer: "I'm actually really pleased with his progress this offseason. I said that to Kiyoshi multiple times. The Red Sox wanted him to get down to, I think, in the 240s, and he's right there. But with him, I think it's just about his strength levels. He's a strong guy. He's powerful. He took our workouts very seriously all offseason. He's definitely ready to play baseball right now."

Help from Miggy

Siempre es un gran placer trabajar al lado del mejor pelotero en la @mlb y compartir momentos agradables y compartiendo ideas para cumplir nuestras meta en este 2017 gracias @miggy24 por esos consejos #teamwork A post shared by Pablo Sandoval (@kfp48) on Feb 14, 2017 at 6:55am PST

Sandoval had another backer throughout the offseason: Detroit Tigers slugger Miguel Cabrera.

"It was him and Miggy the whole time," Ferrer said. "It was great for Pablo, giving him a little extra motivation."

Cabrera has given switch-hitting Sandoval a few tips on improving his right-handed swing, which has produced only a .198 average in 338 at-bats since the start of the 2014 season. And it was Cabrera who introduced Sandoval to Echevarria. In addition to boxers, Echevarria trains football players and lists New England Patriots defensive lineman Chris Long among his first clients.

The idea, according to Echevarria, wasn't to turn Sandoval into a fighter but rather to provide an up-tempo cardiovascular workout. Moving around the ring for three-minute rounds can help with conditioning and footwork. Echevarria also noted that delivering a power punch and throwing a baseball require a similar set of muscles and movements.

And if the Red Sox get into any bench-clearing dustups, well, beware of the Panda.

"I made a joke with him about that," Echevarria said. "I said, 'I hope no one throws at you this year.'

"What I'm trying to do is just kind of add to what you're already doing to make you a little better, your conditioning and whatnot. It's just another thing that Pablo was able to do. If you looked at him before, if you didn't know who he was, you wouldn't think he's an athlete. But if you see him now, you know he's an athlete."

Now comes the hard part: keeping off the weight.

Ferrer sent Sandoval to spring training with a workout program that he can continue to use, with Momose's help, throughout the season. And although Yulimar won't be there to cook for Sandoval on the road, he might seek the help of a personal chef.

"He's just making a lot of changes in his life," Romero said. "The way he looks, he feels great looking in the mirror at himself. Any time you look in the mirror and say, 'Oh my god, I'm there, I'm where I want to be,' that's a good feeling."

Now it's up to Sandoval to make Red Sox fans feel better about him, too.