Phil Mickelson said he was "appreciative" of a rules official after he was saved a stroke for an incorrect drop on Friday at the PGA Championship.

Lefty drove it into the penalty area on the difficult 6th hole at Oak Hill - the same hole where Tom Kim got caked in mud on Thursday - so needed to take a drop. He opted to back as far as he liked, keeping the point of entry and pin in line, and then dropped within two club lengths of that point.

However, the rules changed at the start of 2023 so players can only drop their ball within one club length of the selected point.

The rule change was as follows according to the R&A:

"Back-on-the-Line Relief Procedure: The back-on-the-line relief procedure, often used for penalty area and unplayable ball relief, has been simplified so that the player now drops their ball on the line, and the ball must come to rest within one club-length of where it is dropped."

Luckily for the six-time Major winner, a rules official spotted that he had got it wrong and promptly corrected him on it.

"I ended up hitting it in the hazard and took line-of-sight and came back," Mickelson explained after his second round. "I didn't know that they changed the rule this year, whereby you normally could take the point in line and then you have that two-club-length semicircle.

"And I guess in January they changed that to where you just only get line-of-sight, so the guy came over and saved me a penalty because I had dropped it in the ruling under last year and didn't realize it had been changed, and he came and saved me a stroke, so I was very appreciative."

Someone who did commit a rules breach on Friday at Oak Hill was Cameron Young, who moved his marker on one of the putting greens but forgot to replace it. He received a two-stroke penalty and has missed the cut at nine-over.

The save from the rules official may just have ensured that Mickelson makes his 100th Major championship cut this weekend as he finished up right on the projected cut line at the time. The 52-year-old carded rounds of 73 and 72 for a five-over-par total.

"I came in here very optimistic," he said of his play. "The first two days I've played terrible. I've driven it poorly. I've not felt good with the putter. I haven't chipped great. My irons have been average.

"It makes me optimistic that I still made the cut playing as poorly as I did, and I think if I can get it turned around, I can make a run."