Buster Posey's Future With the former MVP’s offense declining and a rising prospect in Joey Bart, the Giants have a big decision in 2020.

Buster Posey's Future With the former MVP’s offense declining and a rising prospect in Joey Bart, the Giants have a big decision in 2020.

In the heart of the 2010 season, the Giants traded Bengie Molina to create a full-time catching opportunity for Buster Posey, who became a common denominator behind three World Series titles and a recipient of many accolades.

Before the trade, Molina took Posey under his wing and helped teach him about catching in the big leagues.

Will Posey be Joey Bart’s Bengie Molina?

“Yeah,” Posey said. “I mean, I don’t really want to get traded during the middle of the season.”

Touché.

The Giants are in a transition, and so is their six-time All-Star. Posey has two more years on his contract, with the club holding an option for a third year . He’ll be 33 in March. His offensive numbers are at a career low. And Bart, the franchise’s best prospect and catcher of the future, could debut next summer.

Through it all, Posey has played the 2019 season wi th a surgically repaired hip that, according to those who know him best, has prevented him from consistently driving the ball and producing like the Posey of old.

On the other hand, barely a year removed from surgery to fix a labrum tear, shave bone spurs and promote cartilage growth via a microfracture procedure, there’s a sentiment Posey will rebound in 2020 because he’ll have a healthy offseason and spring training to swing free and easy, which he couldn’t do in the months following his operation.

“I still think I have the ability to produce on both sides of the ball,” Posey said. “Each year can be different. Sometimes there are minor adjustments that can make a big difference.”

There’s no question Posey is still producing on the defensive end. The numbers on FanGraphs.com show he remains one of baseball’s top catchers, based on his rankings in defensive runs saved (tied for third) and pitch framing (sixth). He’s throwing out 31% of would-be base stealers, topping the league average of 28%.

Offensively, however, Posey has the lowest batting average, on-base percentage and slugging percentage of his career (.257/.321/.366), and at least part of it could be attributed to the aftermath of his surgery in August of last year.

Posey was on crutches for six weeks, continued his rehab through the winter and eased into spring training games. Opening Day wasn’t a given, but he was behind the plate for the first pitch thrown by Madison Bumgarner.

Manager Bruce Bochy: “It’s at least a year before you get back closer to what you were. Hey, this guy wasn’t able to do much during the winter. We had to watch his workload this spring, and we’ve done it during the season, to be honest.”

Hitting coach Alonzo Powell: “I’ve seen some days he looks really, really good, and there are some other days it seems like he’s coming off that hip a little bit, coming off his back side and leaking forward.”

San Francisco Giants' Buster Posey during Photo Day at Spring Training at Scottsdale Stadium in Scottsdale, Arizona, on Friday, February 27, 2015. San Francisco Giants' Buster Posey during Photo Day at Spring Training at Scottsdale Stadium in Scottsdale, Arizona, on Friday, February 27, 2015. Photo: Scott Strazzante / The Chronicle Photo: Scott Strazzante / The Chronicle Image 1 of / 11 Caption Close Buster Posey’s future: Giants predict revival, but Joey Bart call-up looms 1 / 11 Back to Gallery

Catcher Stephen Vogt: “He’s still learning how to hit with that new (surgically repaired) hip. He hasn’t had an offseason. It’s going to be good enough to play, good enough to get through. But it’s not going to feel back to normal for a full year.”

Bumgarner: “I would say watch out for him next year. I don’t think there’s any way around it. Especially having more time with the hip. I think he’ll have a big year next year. He’s way too good.”

Posey isn’t into excuses. He never blamed his offensive numbers on his hip, not last year when approaching surgery and not this year when coming off surgery. He simply says all players deal with aches and pains to some degree.

Asked directly if the hip has affected his play, Posey said, “I don’t know if I can answer that. The competitor in me is going to say no, right? That there’s stuff I can do? Still, I feel I can still be productive at the major league level. It’s all about adjusting and constantly tweaking.”

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After the surgery, the Giants’ brass hoped Posey’s swing would return closer to normal this year, but in retrospect, that was wishful thinking.

Posey didn’t spend a day on the injured list because of the hip. He was shelved in May with concussion symptoms and in June with a hamstring injury.

If it’s true he’ll continue progressing the further he is from surgery, perhaps we’re noticing the early signs. Two weeks ago, Bochy bumped Posey, in a 2-for-26 funk, down to fifth in the lineup for the first time all season.

Since then, he’s hitting .350 in 40 at-bats (all singles).

“It hasn’t gone the way that I wanted to personally,” Posey said of his season. “You try to learn from everything you go through, good or bad, and reassess. If you try to make the goal about helping the team win, that’s usually going to help you be the most productive player you can be.”

When Posey wasn’t hitting, he was still helping defensively. Working with the staff, calling games, framing pitches and throwing to bases remain invaluable to the Giants, especially with so many young pitchers.

In fact, the man who best knows Posey’s catching abilities suggests his longtime buddy actually has improved on defense. Bumgarner has pitched to Posey in 224 regular-season starts, second most among active batteries (262 for St. Louis’ Adam Wainwright and Yadier Molina) and the most by any Giants tandem since 1900.

“He’s gotten even better,” Bumgarner said. “He’s paid attention to all the new metrics and all the nonsense that they have these days, and he’s made an effort to get even better. We still do a lot of game-calling instinctually and are a little more creative sometimes than going straight to the scouting report. But it’s a good mixture of both.”

Posey has developed a strong camaraderie with Vogt, the Giants’ other catcher who has evolved into a key part of the team. Vogt grew up a Giants fan in Visalia and deeply respected Posey from across the bay when spending five seasons with the A’s. When he was called up in early May, Vogt cherished the chance to work alongside the decorated catcher.

The feeling has been mutual.

When listing the positives in 2019, Posey mentioned several first-year players, including outfielder Mike Yastrzemski, the progress of young pitchers and this: “I really enjoy playing with Vogt this year. I’ve always been a fan, so getting to know him has been great.”

“Obviously, that’s an honor coming from him,” Vogt said. “I’ve admired him from across the way for so long. He’s a true pro. And to meet the person that I admired, it’s been really neat to know he’s even a better person than baseball player. He’s become a friend.”

Asked to elaborate, Vogt said, “He’s a great human. He cares about others. He puts his family ahead of baseball, and that’s the mark of a true professional and will last a lot longer than any accolades you can get on the field.”

Posey said he has made an effort to not allow any on-field frustrations to affect his home life. He and wife Kristen, high school sweethearts from Leesburg, Ga., with their two children, live full time in the Bay Area and are active in the community, especially with their mission to fight pediatric cancer.

But taking his mind off baseball can be “a challenge,” he said.

“All you have to do is ask my wife about that,” Posey said. “You try to look at something like this, a year that hasn’t gone as well as I’d like, it’s a chance to grow in that area as a husband and as a dad and try to understand when I’m done playing this game, there’s a few people in my life who will still be around, and those are the people at home now, so they don’t need to get the bad end of me.”

The season’s final days will be emotional for Posey. Not only is Bumgarner (and Vogt) heading for free agency, but the only manager Posey has had in the majors is retiring.

“The Giants’ marketing people have a good way of tugging at the heartstrings,” said Posey, anticipating a moving sendoff for Bochy, who is destined for the Hall of Fame.

In 25 seasons as a manager, 13 with the Giants, no player has been more valuable to Bochy than his catcher — a three-time champ whose achievements include MVP, Rookie of the Year, Comeback Player of the Year, a batting crown, a Gold Glove and four Silver Slugger awards.

He also caught three no-hitters, including Matt Cain’s perfect game.

Bochy thinks Posey should be a Hall of Fame lock.

“I challenge you to find guys with his resume who are not in the Hall of Fame,” Bochy said. “What hasn’t the guy done? What hasn’t he achieved? What catcher has accomplished as much as he has since he’s been catching in recent history here?

“I know longevity plays a part in this, and he’s going to keep playing. You look at his lifetime numbers, they’re going to grow.”

What will his numbers be in 2020? 2021? Those are questions Giants fans will ponder. Meantime, Bart remains on the fast track after hitting a combined .278 with 16 homers and 48 RBIs in 79 games at Class A San Jose and Double-A Richmond, where he batted .472 in his final 10 games.

Bart, 22, missed time early in the season with a broken hand and will play in the Arizona Fall League.

If Bart follows Posey’s timetable, he would be called up midseason, two years after the draft, and moved into a permanent role. Or because of the injury, perhaps his arrival would be later. Either way, he’s coming. Does that mean Posey will move to first base? Does it mean he would share playing time behind the plate with Bart, who will try playing a corner infield spot in the AFL?

Posey said he’s open to whatever gives the team a better chance to win.

“This is my 10th year now, and I think since year one we’ve talked about when I’m going to move to first,” said a smiling Posey, who added, “One of the greatest gifts you can give to a young player is to have his back and support him whenever he gets here and try to help him grow.

“It’s a game 99% of us really like, so we want to see it get better and better. You try to pay it forward, right? It’s something to analyze when the time comes.”

The season ends in two weeks, and Posey won’t face a winter of rehab like last year. It should allow him to do his normal routine of baseball activities, a refreshing change.

“This winter will be really good for Buster,” Powell said. “He’ll have some time to get in the gym, strengthen his legs, work on his swing and actually be healthy in the offseason.”

Vogt added, “He has a lot left in the tank. He’s one of the greatest catchers to ever play this game. I think next year you’re going to see a truly healthy Buster back at it, and he’s going to have a great year. I believe that wholeheartedly.”

Posey won’t look ahead that far, not when there’s still baseball to be played in 2019.

“The simplistic way to look at it is trying to do what you can to help the team win,” he said, “and if you have that mind-set and get the work in each day, it usually makes the game a little more fun.”

John Shea is The San Francisco Chronicle’s national baseball writer. Email: jshea@sfchronicle.com Twitter: @JohnSheaHey