(Reuters) - Russell Henley incurred a bizarre eight-stroke penalty in the second round at the Mayakoba Classic on Saturday after realizing that one of the balls he had played was different from the rest.
The three-times PGA Tour winner was signing balls for fans when he noticed the discrepancy and received a two-stroke penalty for each of the holes he played the different ball.
"(Henley) suffered a 2-stroke penalty on holes 9-12, 8 strokes in total, for breach of Rule 20-3," the PGA Tour announced in a tweet.
"As Henley signed balls for fans he noticed one ball had a slight difference from the ball he uses. He didn't know how it got in his bag."
Under the "One Ball Rule" used on most professional tours, golfers must use the same brand and make of ball throughout a round.
With the eight strokes added, Henley shot a six-over-par 77 and missed the cut.
He carded 66 in the opening round and without the penalty would have been within striking distance of the lead.
(Reporting by Andrew Both in Cary, North Carolina, editing by Ed Osmond)