Manny Pacquiao gets ready for fight with Jessie Vargas, with a possible eye on Floyd Mayweather Jr.

Manny Pacquiao threw the first sparring punch of his brief Los Angeles training camp Tuesday.

As Pacquiao moves nearer to his Nov. 5 welterweight title fight against Jessie Vargas in Las Vegas, the most interest in him is whether he packs enough power in his blows to provoke Floyd Mayweather Jr. out of retirement.

Pacquiao (58-6-2, 38 knockouts), who’ll turn 38 in December, has spent the majority of this camp balancing his work as a first-term senator in the Philippines with afternoon training for the 27-year-old World Boxing Organization champion Vargas (27-1, 10 KOs).

“I’ve been too busy in the Philippines. I don’t have any time for anything other than my training,” Pacquiao told The Times Tuesday.

There have been some intriguing conversations, however, about the idea of resurrecting a rematch of the richest fight in history that fell far short of expectations last year, when Mayweather cruised to a unanimous-decision victory and Pacquiao revealed afterward he was hampered by a training-camp shoulder injury that required surgery.

Pacquiao’s trainer, Freddie Roach, said he recently crossed paths with Leslie Moonves, the chairman and chief executive of CBS, at a Southland restaurant, where Roach said he told Moonves that Pacquiao wants a rematch with Mayweather (49-0) in 2017.

“Let’s do it again,” Moonves said, according to Roach.

“Can you deliver Mayweather?” Roach asked.

“Yes,” Moonves said, according to Roach.

Stephen Espinoza, executive vice president of the CBS-owned premium cable network Showtime that broadcast Mayweather’s last six bouts, helped broker Mayweather-Pacquiao I after six years of contentious talks. Espinoza acknowledged Tuesday he’s aware of the interest in how Pacquiao will perform on the heels of his impressive unanimous-decision triumph over Timothy Bradley in April.

“Floyd’s been as consistent as he’s ever been. He says he enjoys retirement and promoting and won’t engage with us, even in a joking way, about coming back,” Espinoza said. “So I’m not sure how to get the ball rolling in regard to getting him back in the ring, but I’m not going to give up.

A sharp Pacquiao performance against Vargas “certainly wouldn’t hurt on a conceptual basis … maybe that’ll get Floyd intrigued in the matchup again.”

Mayweather’s close advisor, Leonard Ellerbe, also expressed Mayweather’s interest in retirement and promotion, and Pacquiao denied that he’s reached out by telephone to Mayweather – something that an official close to the fighter had told The Times.

“If there’s a rematch, that’d be OK,” Pacquiao said. “It’s so important to show my career is not over yet, that I’m still here – my strength, my quickness, my speed. It’s still there. God gave me this gift of talent and that’s what I’m trying to show to all.”

Thurman-Garcia is on

Espinoza announced three more Showtime fights for 2017, including a welterweight title-unification card March 5 between Keith Thurman (27-0, 22 KOs) and Danny Garcia (32-0, 18 KOs).

“Probably the biggest fight that can be made in the division today,” Espinoza said. “And we’re keeping the fight off pay-per-view.

“Danny Garcia has … won those fights in a variety of ways, as has Keith. Whether it’s boxing, brawling or punching, these guys find a way to win.”

Showtime will also televise a Jan. 14 super-middleweight unification fight between Las Vegas’ Badou Jack and England’s James DeGale.

Sites for those bouts have yet to be announced but New York’s Barclays Center is strongly positioned to land both.

Shields has a deal

Two-time U.S. Olympic gold-medalist Claressa Shields will make her professional debut Nov. 19 on the undercard for the Sergey Kovalev-Andre Ward light-heavyweight title fight at T-Mobile Arena in Las Vegas.

Shields, 21, from Flint, Mich., will fight on the non-pay-per-view portion of the show against an opponent expected to be named later this week.

“After working hard for so many years and having the honor to represent my country at two Olympic Games, I am thrilled to take the next big step in my career, fighting professionally and leading the rise of women’s boxing worldwide,” Shields said in a statement.

Working-class Joe

At a news conference to formally announce his Dec. 17 bout against former middleweight champion Bernard Hopkins at the Forum, Joe Smith Jr. of Long Island, N.Y., said he draws motivation to close his work as a unionized construction worker.

“I think about that every time I get in the ring. If I lose this fight, I have to go back to shoveling dirt, or jackhammering, or the sledgehammer,” Smith said.

lance.pugmire@latimes.com

Twitter: @latimespugmire