Jorge L. Ortiz

USA TODAY

SAN FRANCISCO - Revamping the rotation was the focal point of the San Francisco Giants’ offseason, as the team spent a combined $220 million on free-agent starters Johnny Cueto and Jeff Samardzija.

Much cheaper and just as important to the Giants’ quest for a fourth World Series title this decade will be the four homegrown players behind them, who represent arguably the top defensive infield in the majors.

First baseman Brandon Belt, third baseman Matt Duffy and shortstop Brandon Crawford were among the finalists for the Gold Glove at their positions last year, with Crawford earning the award over incumbent Andrelton Simmons. All-Star second baseman Joe Panik, who ranked among the leaders in defensive metrics, probably would have completed the quartet of finalists had he not been limited to 100 games because of a back injury.

That infield is not only a major strength but a source of savings for the Giants. Even with Crawford’s six-year, $75 million extension kicking in, the foursome’s combined salary in the upcoming season adds up to a little under $13.5 million, or about two-thirds of what Cueto is making in 2016, including his $5 million signing bonus.

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Moreover, the Giants expect their superb fielding and the move to a pitcher-friendly ballpark will help Cueto and Samardzija bounce back from what was a puzzling season for the first and a miserable one for the second.

“Johnny Cueto pitched in one of the most hitter-friendly parks in baseball most of his career so far,’’ Crawford said Friday, a day before the Giants’ FanFest. “To be able to come here to a bigger park and have some of those fly balls that maybe would have carried at Great American Ball Park get knocked down a little bit by the wind, it’s great for us and great for him.

“And the same thing goes for Samardzija. Both Chicago parks he’s pitched at for most of his career are very hitter-friendly. To come here to a pretty good defense behind him and some of those fly balls maybe getting knocked down, it’s great.’’

Cueto thrived while pitching the better part of the first four months for the Cincinnati Reds, logging a 2.62 ERA before a July 26 trade to the Kansas City Royals that eventually seemed to throw him off his game. Cueto went 4-7 with a 4.76 ERA with the Royals, then had an up-and-down postseason that featured two excellent outings – in the Division Series clincher and in Game 2 of the World Series – as well as a couple of clunkers.

Samardzija tied for the American League high in home runs allowed with 29, a significant contributor to his unsightly 4.98 ERA. Both numbers are likely to shrink when pitching half his games at AT&A Park, which yielded by far the fewest home runs in the majors last season, an average of 0.6 a game.

With two-time 18-game winner Madison Bumgarner heading the rotation, Giants starters figure to improve on last year’s 3.95 ERA, which ranked seventh in the league.

“We’ve got three guys who could be No. 1 starters on other clubs,’’ Panik said.

And plenty of support around them. Not only did San Francisco lead the league in Ultimate Zone Rating and defensive runs saved, but its offense ranked fifth in scoring in the NL and may get a boost with the return to health of Panik and right fielder Hunter Pence, plus the addition of free agent outfielder Denard Span.

However, there are still some questions regarding an infield that includes two players – Panik and Duffy – who have played only one full season in the majors.

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Can Crawford, 29, replicate his offensive exploits of last year, when he set career highs with 21 homers and 84 RBI? Is Belt, 27, past his concussion problems and ready for a breakout season? Will Panik, 25, continue to be dogged by the back problems that sidelined him for all but four games in the final two months? Is Duffy, 25, really as good as he played last season?

“Most of these guys are still early in their careers. The true test when you talk about greatness is the longevity of that greatness,’’ said Giants bench coach Ron Wotus, who doubles as the club’s infield coach. “I believe in Matt Duffy, but it’s a new year, it’s a different scenario for him. Now there are expectations. He’s well aware he needs to go out and do it again.’’

Duffy, an 18th-round pick in the 2012 draft who hit zero home runs in his college career, went from a candidate for a utility role to the starting third baseman in a matter of months, then finished second in the NL rookie of the year voting and made fans forget about former favorite Pablo Sandoval.

With Sandoval anchoring third base, the Giants have had an all-homegrown infield – plus their own drafted and developed catcher in Buster Posey, another Gold Glove finalist – most of the time since Panik took over as the starting second baseman midway through 2014.

But the latest iteration came about more by necessity than design. After Sandoval’s free agent departure following the 2014 World Series title, Casey McGehee joined the club for the 2015 season as his successor, but he floundered so mightily that San Francisco demoted him to the minors and eventually released him.

Enter Duffy, who had played almost exclusively in the middle of the infield in the minors. So naturally, he became one of the National League’s top defensive third basemen – finishing first in UZR and defensive runs saved – and batted .295 with 12 homers and 77 RBI.

Well, maybe it didn’t come all that naturally. Duffy worked constantly at the subtleties of the position and improved markedly over the season. He also displayed remarkable offensive consistency, batting at least .289 every month between May and September.

Duffy, listed as 6-2 and 170 pounds, put on seven pounds over the winter in an effort to retain his strength throughout the season, but he acknowledges he’s not the prototypical third baseman and can’t get caught up in trying to increase his power numbers.

“I’d be lying if I said that doesn’t cross my mind, but at the same time, that’s not my game,’’ he said. “This is a big park. I played in a big park in college and I used to use that as an excuse and try to hit the ball farther, instead of focusing on, ‘Hey, it’s a big park, there’s a lot of room for other hits out there.’ That’s more of my focus.’’

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After missing the playoffs last season, the Giants’ focus is on regaining the even-year magic that has seen them win championships in 2010, 2012 and 2014. They’re happy to do so with players acquired by any means, as their $251 million offseason splurge shows, but there’s an undeniable sense of pride that comes with succeeding with products of their farm system.

Belt said it’s a big deal for the players too.

“We can really trust each other and have fun playing baseball with each other,’’ he said. “Playing with these guys before we got to the big leagues and going through the same things in the minors, we share experiences together, and that helps us play better.’’

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