Padres rookie, 20, could be thorn in S.F.’s side for years

SAN DIEGO — Two games were enough to see that one era in San Diego might be over. With the Giants’ bandwagon leaking oil and losing passengers, and the Padres showing promise that they will be good and exciting for years to come, Petco Park might not be China Basin South anymore, with San Francisco fans outnumbering and outscreaming the locals.

The Friar Faithful will flock here to see Manny Machado and Fernando Tatis Jr. ,a 20-year-old shortstop who serves as yet another reminder that gauging kids is hard.

If Tatis becomes a star, the White Sox will hear about it until the end of time. He was 17 and not viewed as a huge prospect when Chicago sent him to San Diego in June 2016 as part of a deal to acquire pitcher James

Shields. At the time Tatis had

not had one professional at-bat.

Padres general manager A.J. Preller deserves props for seeing something in Tatis that the White Sox did not, and Padres owners deserve equal credit for making Tatis the 2019 Opening Day shortstop rather than finagling his service time by sending him to the minors. ESPN reported that Machado and first baseman Eric Hosmer took executive chairman Ron Fowler to dinner just to lobby for Tatis to be on the team.

Tatis will have his rookie struggles, but in his first two games against the Giants he went 3-for-6 with a walk. He keyed a two-run second inning against Derek Holland on

Friday night when he slammed a backdoor slider off the centerfield wall for a double.

“I looked at it on video, and it was off the plate,” Holland said. “You’ve got to give him credit. He went out and got it. He’s a big-league hitter. He’s up here for a reason.”

Lineup-go-round: The Giants have no concerns about Steven Duggar’s surgically repaired shoulder. While most of the other regulars will get at least one day off in this series, manager Bruce Bochy expects his 25-year-old center fielder to start all four.

“He’s young,” Bochy said. “He can do that.” Evan Longoria was supposed to play all four as well but will sit Sunday after he left Saturday’s game as a precaution after fouling a ball off his calf. Pablo Sandoval could get his first start. Catcher Buster Posey will start Sunday’s game on the bench. Bochy will have Yangervis Solarte in left, Duggar in center and Gerardo Parra in right.

Longoria had not set foot into Petco before last season. Evidently he likes it. In 12 games at Petco he is hitting .321 with three homers in 56 at-bats.

Henry Schulman is a San Francisco Chronicle staff writer.