The last three remaining members of the Giants’ championship core -- catcher Buster Posey, shortstop Brandon Crawford and first baseman Brandon Belt -- achieved a special milestone when manager Gabe Kapler unveiled his lineup for Thursday’s season opener against the Mariners at T-Mobile Park.

Posey, Crawford and Belt each started against Seattle left-hander Marco Gonzales, marking the 10th Opening Day start of their Giants careers to tie Juan Marichal for the fifth-most in the franchise’s San Francisco era. Only Willie Mays (15), Willie McCovey (15), Barry Bonds (14) and Robby Thompson (11) are ahead of them on that list.

“I feel very fortunate to be mentioned alongside all those names,” Posey said Wednesday. “I’ve been nicked up a little bit here the past few years, but the ability to make Opening Day starts and be on the field, I think our training staff deserves a lot of credit. I just feel fortunate to be able to play as long as I have. Craw and I talked about it when we first came up, and I think when he signed his extension, about having the chance to play together as long as we have. I feel fortunate that I have been able to play with him and Belt for as many years as I have.”

Crawford is in even more rarefied company, as he became only the fourth Giants player to make 10 consecutive Opening Day starts, joining Mays, Bonds and Thompson. Posey and Belt’s streaks ended last year, as Posey sat out the 2020 campaign and Belt opened the season on the injured list.

“It's a huge honor,” Crawford said. “I think getting any Opening Day start is an honor, but 10 in a row is pretty special. You start looking at some of the names that have gotten 10 straight Opening Day starts, and it's pretty crazy to see yourself next to some of those names.”

Thursday marked the ninth time Posey, Crawford and Belt have been penciled into the Giants’ lineup together on Opening Day, a sign of the rare longevity the veterans have enjoyed during their tenures in San Francisco. Since 1900, only one other trio of Giants has started at least eight openers: Mays, Marichal and McCovey, who started together from 1964-72, according to the Elias Sports Bureau.

It remains to be seen whether Posey, Crawford and Belt will have the opportunity to share another Opening Day, as they’re each entering the final guaranteed year of their contracts with the Giants. Crawford and Belt will be eligible for free agency at the end of the year, while Posey has a $22 million club option for the 2022 season.

“I think as big league ballplayers we should treasure every season and every game because it could be our last at any time,” Belt said earlier this spring. “But I think that's not really what I’m focusing on. I’m focusing on being productive.”

Why Yaz, Kapler won’t be kneeling for the national anthem

Last summer, several Giants, including Kapler and Mike Yastrzemski, began kneeling for the national anthem to show support for the movement for social justice that rose to the forefront of the national consciousness following the killing of George Floyd at the hands of a police officer in Minnesota.

No Giants took a knee before Cactus League games this spring, however, and Yastrzemski said Thursday that he planned to stand for the national anthem this season.

“For me, that was a way to spark conversation and to get people to notice it, so I feel like I've done that,” Yastrzemski said. “I've publicly let everybody know where I personally stand and how I feel about it. That was ideally what I wanted to do. I will be standing. That was just a way for me to open a way to people to talk to me, to have any sort of conversation and to make sure that there was attention towards that at the time.”

Earlier this spring, Kapler said he chose not to continue kneeling for the national anthem because he preferred to direct the focus toward the actionable steps he was taking to continue the fight for progress and equality. Over the offseason, Kapler launched a foundation, Pipeline for Change, which awards grants to “provide resources and remove obstacles for BIPOC, women, non-binary people and members of the LGBTQ+ community to participate in all aspects of collegiate and professional sports.”

“Different times will call for different actions, and now my actions are focused on work like Pipeline For Change, and the efforts by others to bring about the needed progress in our society,” Kapler said. “So summing it up: I want the stories to be written about the work being done to change what’s wrong, not about whether I’m kneeling or not. And I’m doing that by working to make changes to systems and institutions through my foundation.”

The streak continues

Austin Slater started in left and led off against Gonzales on Thursday, becoming the 15th different player in the last 15 years to start in left field for the Giants on Opening Day. The unusual streak dates back to 2007, when Barry Bonds played his final season with San Francisco.

The other players on the list? Dave Roberts, Fred Lewis, Mark DeRosa, Pat Burrell, Aubrey Huff, Andres Torres, Michael Morse, Nori Aoki, Ángel Pagán, Jarrett Parker, Hunter Pence, Connor Joe and Alex Dickerson.

Alternate training site roster

The Giants will have 27 players continue to train at their alternate training site in Sacramento, including top prospects Joey Bart, Heliot Ramos, Hunter Bishop and Will Wilson. The Minor League season isn’t scheduled to begin until next month, so the quartet will have the opportunity to continue to log game reps in Sacramento until they’re assigned to a specific affiliate.

Marco Luciano and Patrick Bailey, who were also in big league camp with the Giants this spring, stayed behind in Arizona for the beginning of Minor League camp.