For now, he is their new franchise man.
The Giants rewarded the National League MVP and batting champion catcher with a $167 million, nine-year contract Friday, a deal that includes a club option for 2022 that could raise the value to $186 million over a decade.
"It's hard to put into words what I feel right now, just an incredible feeling to know that for the next nine years I'll be a part of this very storied franchise," Posey said. "I'm incredibly humbled to know I'll be a part of that."
He came to the plate Friday night to rousing cheers from the sellout crowd of 42,808 and led off the second inning against Oakland's A.J. Griffin with a single to left. Posey finished 2-for-4 in the 3-1 win.
"That's just great, he's the face of the franchise," pitcher Barry Zito said. "He's the captain of this team as young as he is. That's a huge nod from ownership, from the Giants, to say, 'Pose, you're our guy and we're going to go on with you."
The contract, which is also the longest in Giants history, covers 2013 to 2021 and includes a full no-trade clause for its duration. It surpasses Matt Cain's $127.5 million, six-year contract signed before the start of last season.
"Obviously this is a big day for the Giants and a big day in Giants history," CEO Larry Baer said. "By any measure the largest and boldest commitment we've ever made to a player, and obviously that's a big deal. We don't make these kinds of commitments lightly. ... In order to make a commitment like this we have to look at other measures, too, and look at the person. A nine-year commitment sounds like a lot, but it wasn't scary to us when you look at Buster the person."
In addition, the deal is a record guarantee for a player with fewer than three years of major league service time -- more than doubling the $80 million, seven-year contract Rockies slugger Carlos Gonzalez received before the 2011 season. It also is a record guarantee for a player with fewer than four years of service time, topping the $151.45 million over 11 years that Colorado's Todd Helton was assured in March 2001.
"I don't know if we had a mountain to climb but we had a hill to climb to try to get on the same page," general manager Brian Sabean said. "If he's not the face of the franchise, he's certainly a player that comes around either once every baseball life or not that often."
Posey led the NL last season with a .336 batting average and hit 24 home runs with 103 RBIs to earn the MVP award. He played 148 games for the NL West champions, including 111 starts at catcher and 29 at first base. During the Giants' 2010 and '12 championship runs, Posey hit a combined .244 with four home runs and 14 RBIs.
Two of those homers and five RBIs came in last year's NL division series against the Reds, in which San Francisco became the first team in big league history to rally from a 2-0 deficit to win a five-game series with three straight road victories.
"We've got a group of guys who are not going to rest on what we've accomplished so far," Posey said. "Nine years is a long time. It's exciting. I enjoy the challenge of trying to get better. I enjoy the ups and downs that baseball brings."
The Giants captured their second championship in three years behind the play of the All-Star, who won the NL batting title and MVP award after missing most of 2011 following season-ending left leg and ankle injuries. Posey and Stan Musial are the only players to win two World Series rings and an MVP in their first three full seasons.
Posey knows there will be times things don't go as well as they have so far for him with a World Series win and rookie of the year award in 2010 followed by another title and season of honors last year.
"You get kind of spoiled when you win the World Series in your first year," he said. "I can't see how you can play here and not want to spend your career here."
Posey received his deal a day after the Giants gave Sabean and manager Bruce Bochy contract extensions through 2016.
Posey had been due to make $8 million this year. He instead gets a $7 million signing bonus, with $5 million payable Oct. 15 and the remainder Jan. 15, and his 2013 salary is reduced to $3 million.
He will make $10.5 million in 2014, $16.5 million in 2015, $20 million in 2016 and $21.4 million in each of the following five seasons. The Giants' option is for $22 million with a $3 million buyout.
Posey will earn $57 million for his arbitration years -- the third-highest amount ever -- and $110 million for his free-agent years, a $22 million average annual value. Before Posey, no catcher had earned more than Mike Napoli's $20.8 million in his arbitration-eligible years. Posey's deal nearly triples that.
Posey received his nice payday two days after celebrating his 26th birthday. He will donate $50,000 per year to Giants charities.
He could wind up playing his entire career in the Bay Area -- and the Giants certainly hope that will be the case. The club posted a photo on its Twitter account Friday of Posey, Baer, Sabean, vice president and assistant general manager Bobby Evans, and Bochy -- with the hashtag "SFG4Life."
"It's truly one of the great days for Giants fans," Baer said. "Our fans will be very privileged to watch Buster for the foreseeable future, and ideally Buster will be wearing a Giants uniform for the entirety of his career, which is our goal."
On May 25, 2011, Posey tore three ligaments in his left ankle and broke a bone in his lower leg in a devastating collision at the plate with Scott Cousins, then with the Marlins.
Even with the injury, Posey plans to catch for as long as his body allows it.
"My passion is to be behind the plate for as long as I can," he said. "For anyone who's caught, it's a special position you can't describe until you get back there."
Yet he did once play all nine positions in one game during college.
The 2010 NL rookie of the year is represented by the same agency that negotiated Cain's new deal last year, and both sides were eager to do something again this year to lock Posey up for the long term in San Francisco.
"We're extremely pleased to reach an agreement that keeps Buster in a Giants uniform for a long time," agent Jeff Berry of CAA Baseball said. "Buster and the Giants have brought each other mutual success, and this contract reflects Buster's extraordinary accomplishments in just three years in the major leagues."
The contract includes the following bonuses: $100,000 for NL MVP, $100,000 for World Series MVP, $75,000 for NL Championship Series MVP, $50,000 for a Gold Glove, $50,000 for All-Star Game election, $25,000 for All-Star selection and $50,000 for a Silver Slugger.
In 2010, Posey wasn't even called up from Triple-A Fresno until late May but still batted .305 with 18 home runs and 67 RBIs in 108 games to help the Giants capture their first NL West crown since 2003.
San Francisco gave him $6.2 million when he signed in August 2008 as the fifth overall pick out of Florida State, the richest deal for an amateur joining the Giants.
For Evans in his negotiations, there weren't many players to use as a gauge for having so many accomplishments in such a short career. The Giants entered talks with the idea they would find a way to sign Posey for the long haul.
"The organization will be better off for it each day he's in our uniform," Sabean said.
Information from ESPN's Buster Olney and Jayson Stark, and The Associated Press was used in this report.