“If we were signing them after the 2014 season, we wouldn’t be anywhere near the dollars we ultimately signed them for,” said Bobby Evans, the Giants’ general manager, adding that both pitchers’ durability was part of their appeal. “To bring them here, first and foremost, was really about them: their talent, their past success and the fact that we believe they can have that kind of success here.”

The Giants have reason for optimism. Few organizations nurture pitching so well, and while talent clearly matters most, nearly every factor of the Giants’ experience favors the pitcher. They play in a spacious National League park, and they have a premier catcher in Buster Posey; a highly respected manager, Bruce Bochy, and coaching staff; and a strong defensive infield.

“They’re one of the last organizations that put as much onus on pitching and defense, and you feel that when you come here,” Samardzija said. “In other organizations, that is not apparent whatsoever. It’s: ‘Let’s score as many runs as we can and let the pitcher fend for himself out there.’ ”

There is no defense against a home run, though, and Samardzija allowed 29 last season, tied for the most in the A.L. He allowed two to the Oakland Athletics in a 6-4 loss on Monday — one on a sinker, one on a slider. Samardzija allowed six runs in six innings, swelling his spring E.R.A. to 8.53, but he said he was not concerned.

Samardzija issued no walks and used his splitter to generate ground balls. That pitch is crucial for him, he said, as is the sinker, which he threw less often last season while playing in front of a porous infield defense in Chicago. With the Giants, Samardzija plans to be more aggressive.

“There’s a lot of confidence as a pitcher when you’re looking at those guys behind you,” Samardzija said. “A 3-1 count, it changes a little bit. Just go ahead and put it in play and let those guys work behind you.”

Samardzija is 6 feet 5 inches and 225 pounds, and his long limbs make his timing even more important, said Dave Righetti, the Giants’ pitching coach. Righetti said Samardzija’s mechanics reminded him of A. J. Burnett, who also turned his shoulders as he started his delivery. Samardzija nodded at the comparison.