Mickelson, 52, shot a 3-over par 73 Thursday at Oak Hill Country Club in Rochester, New York.
On Friday, the group was in the earlier wave of tee times, and Mickelson followed up his 73 with a 2-over par 72.
At 5-over par through two rounds, the LIV Golf member currently sits on the projected cutline.
However, his chances at making the cut would have been slimmer had a PGA Championship official not caught Mickelson moments from breaking a rule.
While on the par-4 6th at Oak Hill, Mickelson hit his tee shot into a hazard.
He then took a penalty drop, and was about to hit his third shot when a rules official stopped him and said he had taken a bad drop.
However, Mickelson disagreed, and after a discussion, requested a second opinion.
And when a second rules official arrived, he agreed that it was a bad drop due to a slight rules change for 2023.
Previously, players could drop their ball within a two-club-length area. This year, however, drops must be directly lined up with where the ball crossed the penalty area.
Mickelson was able to fix his drop to avoid a penalty. He went on to make a double-bogey six on the hole en route to his 72.
However, had he not been stopped by the rules official for his improper drop, it would have resulted in an additional penalty.
After his round Friday, Mickelson spoke to reporters about his unique situation:
This wasn't the only ruling situation that Mickelson was involved in on Friday. He also made headlines after he swapped out his golf ball mid-round.