AUBURN, Ala. — Jason Dufner isn’t going to change.

Even if he’s leading the U.S. Open on Sunday with a 10-stroke lead and one putt to make to clinch his first major, he will still look as if he could fall asleep standing there with the putter in his hand.

That’s one of the reasons that residents and his friends in Auburn and at his home club of Moore’s Mill love him.

He is who he is. Auburn grad and fan. Sports junkie. A guy who likes to laugh, just not on camera. TV announcers joke about his stone face. It would seemingly help him get more sponsors. But he’s worked so hard, hit thousands of golf balls and traveled thousands of miles, to get to this point. He has made $6 million in the past two seasons. Why should he change?

“The thing he enjoys most is just being Jason,” said Lon Simpson, Dufner’s friend and money manager. “He just loves to play golf and loves to win.”

Should Dufner notch his third win of the season this week at The Olympic Club in San Francisco — he’s considered one of the favorites — there likely won’t be a Tiger Woods fist pump. There might be a high-five. There will definitely be some Taco Bell, Dufner’s favorite, afterward.

A fist pump is not Dufner. The sleepy-eyed man you see on TV with the hair peeking out from under his cap and the slight belly that comes with being 35 years old isn’t much different than the man people such as Simpson, or personal assistant Johnny Mann, or former Auburn football player Brad Smith see when they are losing to him at golf, pingpong or his new passion, darts.

Dufner is competitive. If it’s not something he’s good at, like pool, he won’t play. If it’s something he likes, he breaks out his iPad, researches it, practices it and attacks it until he’s good at it, such as pingpong.

He likes that sport so much he bought a robot that attaches to his table so that he could practice against it. He once had a lesson after a tournament round in Dallas. And his competitive streak kicks in if he’s playing someone.

Fellow PGA Tour pro Will Claxton isn’t as good a pingpong player as Dufner, but wants to improve. When Dufner was playing in a PGA event, Claxton called to see if he could go to his house and play against the robot. Dufner thought about it for a second.

“I don’t think so,” Claxton remembers him saying. Claxton couldn’t believe it. Dufner was going to keep his advantage. When he’s done playing darts, the board comes down. Nobody practices but him.

But underneath the competitiveness is kindness. Though Dufner usually isn’t one to approach strangers, once he becomes your friend, he’s your friend.

He and Mann met through Simpson. Now, Dufner gives Mann, who is a college student at Auburn’s Montgomery campus, anything he needs, including shirts, golf clubs, even tickets and a flight to this week’s U.S. Open. Dufner is flying Simpson to the British Open, where they will play a few rounds before the tournament. He gave Smith tickets to the Masters. None of them asked. Dufner volunteers his time to help others with their swings or putting strokes, from the oldest member to the junior golfers. All they have to do is ask.

Sometimes, even that’s not necessary.

When tornadoes hit Alabama last year, Dufner drove to the local Sam’s Club, loaded his car with thousands of dollars of supplies, dropped them off at a local church and left. He followed that by starting a foundation to help needy children in the Auburn area.

“He’s more of a big brother,” Mann said.

Dufner entered the golf consciousness at the PGA Championship at Atlanta Athletic Club last year. He led going to the 16th hole and seemingly had one hand on the Wanamaker Trophy. But he hit a bad approach on the uphill par-4 as Keegan Bradley drained an impossible putt on No. 17. The momentum changed, and Dufner couldn’t get it back. Bradley went on to beat him in a playoff.

Afterward, Dufner said he was going to be OK and seemed incredulous that there were any other options. He wasn’t being gracious. It turns out Dufner knew exactly what he was saying.

Mann remembers Dufner telling him early last year, before the PGA Championship, that he was going to play his best on every hole in every tournament. If that resulted in an 11th-place finish, he could live with that. It’s how he began his professional career by earning his way on to the Nationwide Tour in 2001 by being a Monday qualifier at the Hershey Open. He finished 12th, which earned him a spot in the Wichita Open. He won that.

So, though he lost the PGA Championship, he was fine. He did his best. He has stayed true to his words. He wasn’t going to let that loss change him.

He continued his good play. He led the Masters after the second round, but couldn’t finish strong. He finally broke through in New Orleans, posting his first win at the Zurich Classic in late April, a week before he got married. He added another at the HP Byron Nelson Championship last month and finished second at the Crowne Plaza Invitational last week. He has won almost $4 million this year, with three majors to go.

His friends know he has world-class talent. They’ve been smoked by him during practice rounds in which Dufner hits every shot with a 5-iron. Simpson watched him hit a flop shot out of a short-sided bunker with that 5-iron, and then make the putt with it for a 76 to beat him by a stroke. The skill has always been there.

On the technical side, Claxton says Dufner has the enviable ability to take a small swing change, implement it immediately and be confident enough to use it a few days later at a tournament. That’s a rarity for pros, who can take months to get comfortable with the slightest tweak.

On the mental side, they guess that bits of success bred little bits of confidence, which bred more success, which bred more confidence. Getting married may have given him another boost.

Whatever the reason, Dufner is comfortable.

He has some indulgences. He recently bought a Dodge Charger and sent it to Dallas to get painted black. He and his wife, Amanda, recently bought a few acres in Auburn on which they plan to build a home.

But for the most part, he’s still the same. He’s going to hang out at the pool with his wife. He’s going to cut up with his friends. He’s going to enjoy Auburn football and basketball as much as he can.

For Dufner, some things never change.