Jason Vargas of the Mets waits by the plate after...

Jason Vargas of the Mets waits by the plate after a run scored during the third inning against the Padres at PETCO Park on Saturday, April 28, 2018, in San Diego. Credit: Getty Images / Denis Poroy

SAN DIEGO — Forgive the Mets if they wish lefthander Jason Vargas’ season debut, delayed a month by a fractured right hand, had been pushed back a bit longer.

Vargas got rocked by the Padres in the Mets’ 12-2 loss Saturday night, allowing nine runs in 3 2⁄3 innings. The Mets (16-9) are 3-5 on a road trip that will end Sunday with a matinee at Petco Park.

“I just wasn’t good tonight,” Vargas said. “I made some mistakes early and got behind, I got into some situations where they felt good swinging the bat and it just kept rolling from there.”

The rough game for Vargas underscored the Mets’ dearth of reliable starting pitching beyond Jacob deGrom and Noah Syndergaard through the first month of the season.

DeGrom and Syndergaard have a combined 2.43 ERA and 96 strikeouts in 74 innings. The Mets are 9-3 in games started by their co-aces; all three losses came after the starter lasted at least seven innings and the bullpen blew a lead.

Vargas, Matt Harvey, Zack Wheeler and Steven Matz have a combined 6.11 ERA and 60 strikeouts in 63 1⁄3 innings. The Mets are 7-6 in those games.

Vargas’ nine runs matched deGrom’s season total (across 39 innings in six starts).

“Obviously, some of the guys probably could perform better. I think they would say that,” manager Mickey Callaway said. “Our goal is to not worry about what has happened and move forward and just be the best we can be . . . I’m very optimistic that this rotation is going to be good in the long run.”

The Padres’ assault Saturday came quickly, with Christian Villanueva blasting a two-run home run to left-center and Manuel Margot driving in a pair with a triple over the head of centerfielder Juan Lagares in the first inning.

Austin Hedges had five RBIs, including a two-run single in the third. Franchy Cordero ended Vargas’ night in the fourth with a 459-foot three-run homer into the second deck in rightfield, one pitch after pitching coach Dave Eiland huddled with Vargas and catcher Jose Lobaton on the mound.

It could have been worse for Vargas if not for a couple of standout defensive plays. In the second, Vargas’ only scoreless inning, shortstop Amed Rosario made a smooth sliding play up the middle on a groundout. With a man on first, Lagares made a leaping catch at the wall on Villanueva’s fly, robbing him of at least a double.

Vargas allowed nine hits and three walks with five strikeouts, a line worse than any Harvey put up in his four starts before being demoted to the bullpen. Of the 23 batters Vargas faced, 12 reached base.

It was not the debut the Mets were looking for from Vargas, who was signed to a two-year, $16-million contract early in spring training to be a stabilizing presence in a rotation that endured significant injuries last season.

A fractured glove hand — he was hit by a line drive during a minor-league game — late in camp forced him to undergo surgery. He pitched in several simulated games and one formal rehabilitation game before returning.

“There’s probably that to factor in,” Callaway said. “He threw behind a screen for a month and got to face live hitters without a screen one time. I’m sure some of that was a factor.”

Bright spots were few for the Mets, who managed only four hits. Yoenis Cespedes saved them from being shut out with a two-run homer to center in the sixth. Seth Lugo lasted 2 1⁄3 innings, helping to minimize the damage on the bullpen.

It would have taken a significant outburst to undo Vargas’ damage.

“I know Vargas,” Callaway said. “He’s had those before, he’ll have them again. But he’s going to battle in the meantime.”

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