FORT MYERS, Fla. – In October, it will be 20 years since Pedro Martinez last pitched for the Red Sox.

But the Boston legend, who’s already nearly a decade into being a Hall of Famer, hasn’t let retirement stop him from pitching in for the team he loves.

As he did last offseason, Martinez hosted Brayan Bello at his home in their native Dominican Republic. There, like a Jedi Master training a Padawan, he helped the young Red Sox pitcher hone his craft.

“I was able to work out with him three or four times,” Bello said via Sox translator Carlos Villoria Benitez on Thursday. “It was a very good time that I spent with him.”

“I had a few outings at the end of the year that weren’t the best, so for me it was, I needed to tackle that right away. I wanted to tackle that right away, being aggressive from the first day (of the offseason).”

Much of Bello’s first full season in the Majors was excellent. After allowing five earned runs in his season debut, he posted a 2.70 ERA across his remaining 14 starts before the All-Star break, holding opponents to a .231 average and .660 OPS and never allowing more than three earned runs. Kenley Jansen began calling him “Pedro Junior.”

But in 13 starts in the second half of the season, Bello’s ERA ballooned to 5.58, and he got hit hard: a .300 average and .880 OPS. He allowed at least three earned runs in each of his five September starts, and 13 combined over the final two games.

Frustrated and dissatisfied, he dove into an offseason of hard work. Among the results of his time with Martinez is an upgraded slider.

“When I got there, my slider wasn’t in the best shape, so he gave me a few tips,” Bello said. He saw results almost immediately.

“That same day, I was able to get a good grip on it,” the 24-year-old right-hander said. “I was throwing it consistently, and then in the next few days, I was gaining more confidence with it.”

Bello threw 463 sliders last year, going to the pitch 17.7% of the time. He actually saw some improvement against right-handed hitters; he sent 308 sliders their way, and their batting average and slugging percentage against the pitch dropped nearly 20 and 10 points over the previous season, respectively. However, lefties feasted on his sliders to the tune of a .370 average and .519 slugging percentage.

A revamped slider can improve Bello’s pitch mix considerably. He already boasts a dominating sinker and solid changeup, his two most-used pitches last year, as well as a four-seam fastball.

Growing up, Bello idolized Martinez. In recent years, Martinez has become a fan of Bello’s, as well, not only mentoring the young right-hander, but championing him.

“I saw a young kid with a really high ceiling, that all he needed was to build confidence,” Martinez told the Herald at spring training last year.

Bello showed off the slider on Thursday, throwing live batting practice. “I felt more comfortable with that pitch,” he said. “I feel like I can throw it in any count. Today in live BP, I used it and felt really good about it, so it was a good offseason for that pitch. I feel like my confidence is up with that pitch.”

Bello grew up a huge fan of Martinez, and the feeling has become mutual over the years.

“I think he is way more talented than I am,” Martinez raved to the Herald last February. “I wish, I WISH I had the talent that Brayan Bello has, when I was coming up. He’s way more talented than I am.”

“It feels great to be able to share time with him, for him to share his experience with me,” Bello said. “Every time I’m kind of talking to him, I just remember all the things that he’s done, Cy Youngs, World Series, and everything.

“It’s nice (when) somebody like that is investing time in you, and that’s something that I don’t take for granted, and that’s something that I really appreciate and really like.”

Bello’s offseason program drew rave reviews from his manager, too.

“It’s a lot different than last year. I think physically, he’s way ahead,” Alex Cora said. “It’s not that he took it for granted (last offseason), but he was very specific this offseason, the things he needed to work on, especially body-wise. You see him around, he’s grown into a man now. He’s gained some weight, he looks stronger, he did an outstanding job in the offseason.

“Now, it’s about his buildup and being ready for the opening series.”