That is what Madison Bumgarner and Buster Posey are. Care to argue? Name another pair with six World Series championship rings between them at any age, much less long before either turned 30, one a National League Most Valuable Player, the other a World Series MVP.

“They’ve had a nice run,” said pitching coach Dave Righetti, who has watched the pitcher from North Carolina and catcher from Georgia grow up together in baseball.

In ranking them among the game’s best, Righetti invoked a quote from the late football coach Bum Phillips, who was referring to running back Earl Campbell when he said, “I don’t know if he’s in a class by himself, but I do know when that class comes together, it sure doesn’t take long to call the roll.”

Manager Bruce Bochy last week finally stated what has been obvious for years. No matter what kind of lineup he pens on other days, Bochy wants Posey to catch Bumgarner, as he has in three-quarters of the left-hander’s 183 regular-season games. The percentage would be much higher had Posey not been hurt for four months in 2011.

The Giants drafted Bumgarner out of high school in 2007, Posey out of college a year later, both in the first round. Their rise as baseball brothers started with the commensurate expectations and grew with an early ease in their relationship.

“I think both of them are pretty talented to begin with,” Righetti said. “They both kind of came up together at almost the same time. When they did, I noticed there was a rapport between the two of them right off the bat.”

They met in the 2008 instructional league. What struck Posey first about Bumgarner was his size.

“I just remember thinking how big he was for being just 18 at the time,” Posey said. “His presence was more mature than 18 from what I remember.”

Bumgarner’s earliest impression of Posey was cast the following season when they were teammates with Class A San Jose, the moment when Bumgarner first understood the smarts that the Giants’ front office saw when they scouted the catcher at Florida State.

Posey drilled a hit against the opposing pitcher. Bumgarner can’t remember if it was a double or a homer. When Posey returned to the dugout, he stated firmly which pitches he would see in the next at-bat, and in which order.

Bumgarner watched the encounter unfold exactly as Posey had predicted. The result was a single.

They refined their games in the minors together and reached the majors a month apart in 2010. (Each had a brief call-up in 2009.) Their big-league time was minimal before they reached the postseason as rookies.

The night before the Giants celebrated their first San Francisco championship in Texas, Bumgarner bulldozed his way into the sport’s consciousness when he pitched eight shutout innings in Game 4 of the World Series, on the road.

Bumgarner and Posey were as one that night, working together like parts in a Swiss watch, as if Michael Tilson Thomas were standing between them directing each pitch with a baton.

“I love that game,” Posey said. “I get chills thinking about it, because he was 21 and I was 23 and we’re playing on the biggest stage. I think both of us just played so freely and with confidence.

“We felt our manager and our coaching staff had confidence in us already at that time. It’s one of my favorite memories in my career. He was in such control the whole game.”

The rapport and friendship has only grown. Posey and Bumgarner dress at adjoining lockers at Scottsdale Stadium. Posey likens their relationship to big brother and little brother, with Posey always poking and provoking Bumgarner until the latter blows his top.

Why does Bumgarner let Posey get under his skin?

“I wish I knew,” the pitcher said.

Posey understands the consequences if he finally goes too far.

“I’m watching my back,” he said, kind of smiling, kind of not.

The Giants are fortunate to have such an accomplished catcher working with Bumgarner. Imagine if they ran through a parade of catchers, especially young ones, as some teams do. Posey recalls as a rookie the intimidation of catching Randy Johnson and believes a neophyte would feel the same catching Bumgarner.

If Posey loves to push Bumgarner’s buttons in the clubhouse, he rarely needs to provoke the pitcher on the mound. If anything, Posey needs to calm him at times.

“Conversations generally have always been easy for us,” Posey said. “I think we have a similar competitive nature. We might show it outwardly a little differently at times.”

Perhaps their Southern roots made the conversations easier from the get-go, although Bumgarner noted that players with similar lifestyles and backgrounds do not always mesh. It’s an easy answer, though not necessarily the right one.

Even if the Posey-Bumgarner pairing might be one of those happy accidents, the effect is clear. When they work as one, they work better.

“I’d like to think that it doesn’t matter and that you could compete and win under any circumstance,” Bumgarner said. “But it definitely takes one of those variables away.

“I know what I’m getting with him back there. That does make it easier. There’s a lot going on in a game. It just keeps you from having to think as much. We’re just comfortable with one another.”

Henry Schulman is a San Francisco Chronicle staff writer. Email: hschulman@sfchronicle.com Twitter: @hankschulman