– Stephen Gonsalves, the Twins’ top-rated pitching prospect, has the mechanics down cold. The lefthander can describe the technique, can demonstrate the arm action, can speak from experience about the hard work involved.

Oh, he knows pitching, too.

But if baseball wasn’t his career, he might be back in San Diego working on a tuna boat, which he did for two offseasons. Pole fishermen, like his father, uncle and grandfather, work with two partners, using long bamboo poles and whipping the 150-pound tuna out of the water, over their shoulders and onto their boats, over and over again for hours at a time.

It’s as strenuous and exhausting as it sounds, Gonsalves says, but if baseball doesn’t work out, “that would be my fallback, probably,” and it’s difficult to tell if the stereotypically laid-back southern Californian is kidding. “It’s good money — once you work your way up.”

Fortunately, he has found another profession where that’s true, and he has almost worked his way up to the top. Coming off a 2017 season in which he dominated the Class AA Southern League with a 2.68 ERA, struck out 96 hitters in 87 innings, and was ranked as the No. 3 prospect and top pitcher in the Twins system by mlb.com, Gonsalves comes to camp as a legitimate candidate for the 2018 rotation — though admittedly still a long shot. Ask him to rate his chances of coming north with the Twins, Gonsalves cracks, “Rochester is north, too. I’m taking it a step at a time.”

But someday he will be the Twins’ Opening Day starter. That day is Thursday, actually — the 23-year-old has been given the assignment of starting an exhibition against the Gophers at Hammond Stadium.

“It’ll be my first college game,” Gonsalves jokes, since he was drafted straight out of Cathedral Catholic High in San Diego in the fourth round of the 2013 draft.

It’s also a good first chance to try to impress manager Paul Molitor and Chief Baseball Officer Derek Falvey, who must choose a fifth starter from a lengthy roster of candidates. Given that it’s still February, Gonsalves intends to use the session to refine his motion and give each of his four pitches a look. His fastball reaches 92 miles per hour, his changeup is effective off it, and he is gaining confidence in his slider.

Then there is his curveball, and don’t worry, he knows what you think of it.

“My curveball gets hate [on the internet], but I think it’s a good pitch,” he said of the pitch, which some scouts believe might prevent him from being a true staff ace. “I’ve read a lot of bad stuff about my curveball. I know it needs work.”

Twins pitching coach Garvin Alston downplays that relative weakness, saying the solution will come with more experience, but also from another source.

“Better fastball command allows for everything else to get better,” Alston said. “If that improves, everything else will too.”

Gonsalves figures things will improve this year, anyway. For one thing, he limited his offseason workouts, pitching off a mound only twice. That’s after exhausting himself the previous winter, when he tried to follow up a terrific 140-inning 2016 season at Class A Fort Myers and AA Chattanooga (he posted a combined 2.06 ERA) with a stint in the Arizona Fall League. He came down with a sore shoulder as a result, cutting his stay to only four ugly starts, and the problem recurred when he reported to 2017 spring training.

“I didn’t really have a break. I did 10 bullpens before I even got here,” he said. “This year, I’ve done only two, so I’m feeling a lot more fresh.”

He also believes he has solved that shoulder soreness by shortening the backward reach in his windup.

“Working with the [physical therapists] last year, that’s what we learned — don’t go as deep behind me,” he said. “Part of my problem was that I would get too far behind my back, and overcompensate a little bit.” By adjusting his windup, “I kind of gained a little bit of [velocity] last year, because it makes you use your legs your legs a little more.”

The combination, and his proximity to the majors, has Gonsalves eager to see where this season takes him. “I have a pretty good idea where I line up right now,” he said, and he won’t be disappointed if it’s not Minnesota — yet.

“The way I see it, they used 36 pitchers last year, and 16 starters. So we’re all going to play a part,” he said. “This is going to be a really good team. I’ll work that angle and hope to help us get to the World Series.”

Beats working on a tuna boat, right?