Mark Hensby was a late add to the field at this week’s Palmetto Championship. He also was an early withdrawal after adding 10 penalty strokes to his opening-round score.

The 49-year-old Aussie, trying to make his first PGA Tour cut in five years, was 2 over through his first eight holes Thursday at Congaree when he noticed something strange with his golf ball. The Titleist ProV1 had an unfamiliar small dot on it.

“I asked my caddie, ‘Hey what's this dot on the ball? I've never noticed this before; did they do something with the new pro V1?’” Hensby told PGATour.com. “And he didn’t know, so I asked my playing partners, and they were like, ‘That's a low spin ball.’ Now I don't use this ball, so there was a lot of confusion where it came from – none of my others had the dot – but we knew I had played the wrong ball.”

Hensby, who figured he had begun playing the incorrect ball after depositing his third shot into the water on the fourth hole, was subsequently docked two strokes for every hole he had played with the wrong ball. In line with Model Local Rule G-4, Hensby was penalized 10 shots in total.

He would play his final 10 holes in 1 over to card a 13-over 84.

“After I got the penalty obviously it was tough from that point on, and it was a shame because I knew my tournament was over,” said Hensby, who didn’t even make it to Friday after pulling out of the event. He told PGATour.com that he felt stiff after driving a moving truck from Scottsdale, Arizona, to San Antonio, a 14-hour trip, last Sunday.

As to how Hensby ended up with the stray Titleist ball, it was later determined that he and Pat Perez accidentally switched balls while hitting putts on the practice green before the round.

“Somehow I picked up one of Pat’s balls and he ended up with one of mine,” Hensby said. “I only found this out because Titleist wanted to get to the bottom of it. I thought they had a wrong ball in the sleeve that I had. If you look at both balls it's hard to know the difference. It’s not like one is black and one is red. They're both black, but one has a small dot on it, and one doesn't.

“Unfortunately, I didn't notice that. I’m glad he didn’t use mine.”