NEW YORK (CBSNewYork/AP) — Some main attractions are missing as the Mets host the San Diego Padres in their season opener Monday.

Chase Headley, the biggest bat on the Padres and last season’s NL RBI leader, is sidelined for a few weeks with a broken thumb.

Johan Santana’s future is far more precarious.

After re-tearing the anterior capsule in his pitching shoulder, the one-time Mets ace is scheduled for another surgery Tuesday that he hopes can save his career.

So, the opening day assignment has gone to Jonathon Niese, suddenly thrust into the role of No. 1 starter for a team that traded popular Cy Young Award winner R.A. Dickey during the offseason.

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“It’s Jon Niese’s turn. He’s now that guy,” manager Terry Collins said Sunday at Citi Field.

Born on the day the Mets won the 1986 World Series, Niese established career bests across the board last season when he went 13-9 with a 3.40 ERA in 190 1-3 innings.

Die-hard fans ready to root on the Mets (credit: Monica Miller/WCBS 880)

Die-hard fans ready to root on the Mets on April 1, 2013 (credit: Monica Miller/WCBS 880)

The fast-working lefty is facing a Padres lineup also minus promising young catcher Yasmani Grandal, suspended for the first 50 games after testing positive for testosterone. Left fielder Carlos Quentin is ready to go, though, after he was slowed this spring with discomfort in his surgically repaired right knee. Top prospect Jedd Gyorko takes over at second base.

Niese said this spring he won’t try to “fill anyone’s shoes.” But he acknowledged Sunday that he’ll probably be a little anxious on Opening Day.

“It’s kind of sunk in now that we’re here at Citi Field,” Niese said. “I went out on the field and just looked at everything, and it feels nice to be back.”

New York announced the decision to go with Niese on March 21 — the same day David Wright was appointed team captain — after Santana stalled at spring training.

“I’m not going to treat it as an opening day,” Niese said. “I’m going to treat it as a midseason start. I’m going to prepare the same and just be ready for it. I don’t think we really have an ace on this staff. I think everybody contributes equally.”

Pitching for the Padres is Edinson Volquez, making his third consecutive opening day start. He got the ball last year for San Diego and in 2011 with Cincinnati.

Solid arms for sure, but this matchup of fourth-place teams that held their money tight last winter probably won’t make many national headlines on a day when the likes of Stephen Strasburg, Justin Verlander and Felix Hernandez are on the mound.

Not to mention across town, the Yankees are hosting the rival Boston Red Sox at the exact same time. Still, the die-hards will be out in force in Queens.

Mets fans tailgating on Opening Day (credit: Monica Miller/WCBS 880)

Mets fans tailgating on Opening Day (credit: Monica Miller/WCBS 880)

“It’s a fresh start. As a Mets fan, you know how it is,” one fan told WCBS 880’s Monica Miller.

“You get to bust out all your tailgating stuff, it starts to get nice,” another fan told Miller.

Mets fans tailgating in the Citi Field parking lot prior to the game said there’s a real sense on camaraderie among the fan base.

“I like to always think that anybody that supports the Mets are really true fans because you don’t just wake up one day and decide, ‘Hey, I’m going to be a Mets fan and take all the abuse. Especially around here with Yankee fans,'” a man told Miller.

Fans said it’s important to think long-term on Opening Day because it’s a long season.

But New York is facing a tough test against Volquez.

“I love Eddie out there, especially that first game with his stuff. You know he might throw a few pitches but he’s going to get outs. He’s nasty,” Padres outfielder Will Venable said.

Volquez, an All-Star with the Reds in 2008, has a tendency to be wild. But he played a pivotal role for the Dominican Republic team that won the World Baseball Classic this spring.

The right-hander was 11-11 with a 4.14 ERA last season after he and Grandal were part of the four-player package Cincinnati sent to San Diego for pitcher Mat Latos in December 2011.

“Edinson Volquez is very capable of throwing a hell of a game,” Padres manager Bud Black said. “I think our guys are physically and mentally ready to do it. They’re in a good frame of mind.”

Of course, the Mets are optimistic at this stage as well.

Nearly the entire squad showed up for a voluntary workout Sunday to prepare for the opener. Wright and second baseman Daniel Murphy are expected to play after both were sidelined by ribcage injuries until just a few days ago.

“I feel good physically,” said Wright, who was on a hitting tear for Team USA when he got hurt at the WBC. “It would have been nice to have maybe a few more at-bats toward the end, but I didn’t have that luxury.”

Collins addressed his team Saturday night, marking the end of a long spring training.

“It’s time to get after it. It’s time to start putting together all the things that we worked on,” he said. “I told the guys yesterday, ‘If you’ve ever wanted to be on the biggest stage, this is it.’ There’s nothing like opening day in New York.”

NOTES: Collins and trainer Ray Ramirez watched closely as backup infielder Justin Turner (calf) ran the bases at Citi Field. Turner was deemed healthy enough to remain on the roster, and the Mets made their final cut by optioning 3B-1B Zach Lutz to Triple-A Las Vegas. … Rusty Staub, a member of the Mets’ Hall of Fame, threw out the first pitch Monday as the club celebrates the 40th anniversary of its 1973 pennant. … The Mets honored hundreds of Hurricane Sandy responders and volunteers in a ceremony on the field before the 1:10 p.m. game. The team donated 1,000 opening day tickets to storm responders and those affected by the destruction. … Days before the opener, the Mets were offering free seats to games later in the week to fans buying opening day tickets. … Despite losing their first eight openers, the Mets are 33-18 on opening day — the best mark in baseball.

Mets fans — will 2013 be Niese’s best season yet? Be heard in the comments section!

(TM and © Copyright 2013 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2013 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)

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