AUGUSTA, GA. – When he missed the cut at the 2022 Masters, Brooks Koepka twice punched the window of the car carrying him from Augusta National Golf Club. Neither he nor the glass wound up on an injury report. "I guess Mercedes makes a pretty good back window," he said.

Friday, when he finished the second round at the 2023 Masters, he was in the lead, having shot a 67 to give him a three-shot advantage over Jon Rahm, who finished only 10 holes because of threatening weather.

Koepka has always thrown his best haymakers during major championships, and he's using this Masters to re-establish his credentials, tell his comeback story and provide constant reminders of just how tough and ambivalent he can be.

Koepka is a shrug in human form, which might be why it takes a major to grab his attention. He has won as many majors (four) as other PGA Tour events. With a healthy knee and the reappearance of his short, powerful swing and clutch putting, Koepka looks prepared to make it five.

Which is an interesting number, given the events of the past two days.

On Thursday, cameras captured his caddie, Ricky Elliott, saying "five" twice on the 15th fairway, in the vicinity of player Gary Woodland and his caddie.

Giving or asking for advice, such as club selection, would be a two-shot penalty, with the player being responsible for his caddie's actions.

The Masters reviewed the incident and interviewed the players and caddies and determined that no rule had been broken. Koepka said he thought Elliott was telling an on-course reporter that Koepka had just hit a 5-iron.

Social media also made much of the fact that, in one camera frame, Koepka appears to be holding his left hand rigid, in what could be interpreted as an indicator that he hit a 5-iron.

Koepka said that he and Elliott did not share information, and that Woodland later asked him what club he had hit, an indication that Woodland didn't learn anything on the fairway.

What was more interesting than the accusation was Koepka's reaction. He didn't display anger. He just shrugged it all away.

The two subjects that inspire emotion in Koepka are major titles and the knee injury that made him question whether he could ever contend on the PGA Tour again.

He left last year for the LIV Tour. Unlike Phil Mickelson, he doesn't have his LIV team name on his clothes or golf bag. Would leaving have been a tougher decision had he known he could play this well?

"Honestly, yeah, probably," he said. "If I'm being completely honest, I think it would have been. But I'm happy with the decision I made."

Winning the Masters this week would erase one potential ramification of that decision. The Masters has made qualifying for the tournament more difficult. If Koepka wins the green jacket, he will have a lifetime invitation, and he will be tied for 15th in golf history for most majors won.

A Masters victory would also leave him a British Open title short of the career grand slam, which only five players have won.

"Yeah, the whole goal is to win the Grand Slam, right?" he said. "I feel like all the greats have won here and they have all won British Opens as well. I guess it's one more box for me to tick, to feel I've done what I should have accomplished in this game."

Koepka told the media and his friends on the PGA Tour that he wouldn't leave for LIV. Then he did.

On a Netflix special, he fretted that he could no longer compete with the best in the game, hinting that LIV's guaranteed money and easier schedule better suited a player recovering from a severe knee injury.

Now he's back atop a major leaderboard, and his next shrugs might come within the confines of a green jacket.