Phil Mickelson said he "wasn't really thinking" when he incurred a two-stroke penalty in bizarre fashion during the final round of A Military Tribute at the Greenbrier.
Three weeks on from causing controversy at the U.S. Open by deliberately putting a moving ball, Mickelson found himself at the centre of another unusual rules violation on Sunday.
The five-time major champion patted down some long fescue rough in front of the tee box before hitting his opening shot on the seventh hole.
Mickelson immediately realised he may have erred, telling his playing partner: "I'm not sure what I did then is legal."
After teeing off, he duly consulted a rules official, who confirmed the veteran had violated Rule 13-2 by "improving his line of play".
Asked to explain what happened after his round, Mickelson told reporters: "Oh, I just ... I wasn't really thinking. I just had a few bonehead moves today.
"You can move stuff on the tee box, but I've been working on this really low shot for the next two weeks, and there was some fescue in front that was low, and I stepped on it.
"Right when I did, I thought, oh, my goodness, that might be a penalty. I told my partner, and we asked Robbie [Ware] the rules official, and sure enough it was.
"It was just one of those things that I wasn't really paying attention or thinking. If we were on the tee box, no problem, but it was just a foot in front, and it's just one of those things. So you take your penalty and you move on.
"It's happened before, not just at the [U.S.] Open, but a number of times. A lot of times guys just inadvertently do things, and I just wasn't thinking. I wasn't really having my best day focus-wise."