In 2017, infielder Jason Vosler hit 21 home runs at the Cubs’ Double-A affiliate in Tennessee, more than his previous three Minor League seasons combined. It marked the first of three consecutive 20-home run campaigns for Vosler, an impressive feat considering he hadn’t hit for much power at the beginning of his professional career.

What led to the noticeable power surge?

After hitting only three homers in 2016, Vosler, now with the Giants, decided to make “a swing preparation change” to help tweak his mindset at the plate.

“It wasn’t necessarily like, ‘Hey, I want to hit fly balls,’” Vosler said during a Zoom call with reporters on Wednesday. “It was more, ‘All right, I’m going to ditch these ground balls. I’m going to start trying to beat the center fielder with line drives during batting practice, those rising line drives with backspin. I think it just kind of organized my swing in a way that produced that more consistently, and then more balls started going over.

“It wasn’t a huge mechanical change or anything. I think it was almost the thought of hitting more line drives kind of organized my body in a way that, probably some changes did occur, but they weren’t that intentional.”

Vosler, 27, found inspiration on Twitter and YouTube, where he consumed hundreds of videos of the top sluggers in the game, including Giants legend Barry Bonds, who Vosler vividly remembers watching play at Yankee Stadium when he was 9 years old in 2002.

“I watched Bonds a lot,” Vosler said. “Miguel Cabrera was another big one that I’ve watched a lot. And then [Mike] Trout and [Albert] Pujols. I would say those were probably the four I watched the most, with Bonds probably being the leader there. ... I would say [Bonds is] probably the best hitter of all time. If not the best, you’re probably putting him at top three at the very worst. All around, he seems like somebody who’s good to watch.”

Vosler, who entered Wednesday batting .313 (10-for-32) over 11 Cactus League games this spring, is already showing the offensive potential that made him an intriguing pickup for the Giants in the offseason. Vosler has yet to appear in the big leagues and spent last summer working out at the Padres’ alternate training site, but the Giants coveted Vosler enough to sign him to a Major League deal in November.

The left-handed-hitting infielder initially looked like he might be blocked from the Opening Day roster after the Giants signed another veteran with a similar skillset, Tommy La Stella, last month, but Vosler has been getting looks at third, second and first base, and left field, to try to create as many paths to the Majors for himself as possible.

A spot could eventually open up at the corner infield given the health issues looming over third baseman Evan Longoria and first baseman Brandon Belt. Longoria has yet to start a game at third base due to plantar fasciitis, though he could be ready to play defense at some point next week. Longoria said he isn’t too concerned about being ready for Opening Day.

Belt is a bigger question mark, as he’s coming off right heel surgery, and he has also been slowed by a bout of mononucleosis. It’s unclear when Belt will make his spring debut, but he has been taking batting practice on the field, taking ground balls and running.

If either veteran is unavailable for the Giants’ season opener in Seattle on April 1, Vosler will likely have the opportunity to step in and finally fulfill his big-league dream.

“It’s always been the dream to get there,” Vosler said. “I don’t want to think too far past today or tomorrow. I just kind of let that take care of itself if I take care of business today.”