PHILADELPHIA -- This will not be Bryce Harper's first big moment in the big leagues, but it will be his first big moment with the Phillies.

It will probably play out like this: Shortstop Jean Segura will walk to home plate in the bottom of the first inning on Thursday afternoon at Citizens Bank Park, where the Phils play the Braves on Opening Day. Harper, who will hit third in manager Gabe Kapler’s lineup, will emerge from the dugout with his helmet and bat, and head to the on-deck circle.

The sellout crowd will begin to buzz.

Segura’s at-bat will end and Harper will walk to home plate for his first official plate appearance with the Phillies since signing a 13-year, $330 million contract on March 1.

Harper will get a standing ovation.

Nobody knows what will happen after that, either in that at-bat or over the next 13 years. But Harper believes he knows how he will feel in that moment.

“It’s funny,” Harper said before the team's workout on Tuesday afternoon. “I was talking to Gabe probably the first or second day of Spring Training. When I step in the batter’s box, my heart rate, everything like that, is controlled. It is my sanctuary, it is what I do. I get more stressed out driving down the highway or freeway in traffic, I am super nervous about that or anxiety.

“When I step into the batter’s box, 45,000 people going crazy, I would love to put a heart rate monitor to see what it looks like because I enjoy those moments. I enjoy the craziness. That is what I do. I love that. I love those situations. I think it is that jump-out-of-a-plane kind of feeling; you get into a batter’s box, bottom of the ninth, bases loaded or even the first game of the series, first game playing somewhere new. I am looking forward to that, looking forward to seeing what that feels like again and being in those situations of high intensity, emotion and anything like that, so I am very excited.”

Harper first career big league plate appearance came April 28, 2012, against Dodgers right-hander Chad Billingsley at Dodger Stadium. Harper grounded out to the pitcher. Harper’s first plate appearance with the Nats at Nationals Park came against D-backs right-hander Trevor Cahill on May 1, 2012. He struck out swinging.

“My first AB in D.C., I definitely remember vividly,” Harper said. “So that was pretty cool being able to get my first standing [ovation] from my home fan base. This is a new chapter. I think this is definitely going to be a little bit different, coming from Philly instead of DC. I am looking forward to that and looking forward to being out there and wearing a Phillie uniform, and just being out there Day 1, and I am very excited to be in front of a new fan base and see what it is all about.”

Who’s on third?

Kapler said Maikel Franco will be his third baseman on Opening Day. Franco and Scott Kingery entered Spring Training competing for playing time.

“They both did a great job this spring. There doesn’t have to be one guy who won the job and one guy who lost the job,” Kapler said. “I don’t see it like that. Every day they are going to be battling for opportunities and reps. Scott’s just not battling for reps at third base. He’s battling for reps in center field, and to find ways to get rips at shortstop and second base to give Jean Segura and Cesar Hernandez a blow.”

Who’s closing?

Kapler reiterated that he will not have an official closer for the ninth inning. It could be David Robertson. It could be Seranthony Dominguez. It could be Hector Neris.

“I can tell you the guys I think will be pitching in the highest leverage situations,” Kapler said. “For all the reasons you’d expect, I wouldn’t share information like that.”

Kapler mentioned Robertson, Dominguez, Neris, Pat Neshek and others.

“If you look at the Braves’ lineup constructions, you’re going to have to do a little mixing and matching to get the best in the seventh, eighth and ninth innings,” Kapler said.