"The golf course is too big for me, and with my declining skills and length, I won't be playing that," said Watson, who hasn't made the Masters cut since 2010. "The toolbox is kind of half-empty with the tools I used to be able to play good golf. Those tools are missing right now, or pretty rusty -- rusty like me."
This news comes on the heels of Watson playing in his last Open this week -- unless the 65-year-old finds a little magic on the Old Course.
"It would be nice if I ended up in the top 10, to be able to extend five more years," he said. "I don't foresee that, although I'm playing pretty well.
"I kind of just hope that I make it to Sunday. When you get to that position in your career, you're just hoping to make it to Sunday, then it's really time to hang them up."
During a long pre-tournament news conference Wednesday, Watson often waxed poetically about his golfing mortality, philosophizing on the impending end of a career that saw him claim eight major championship titles.
"Over the years, I've made my share of wrong decisions, but do I have regrets? The only regret I have is that it's the end," he said. "It really is. It's the end. It's 40 years. It's the end. And I regret I don't have the tools in the toolbox to be able to continue on.
"It's a little bit like death. The finality of the end is here. But what tempers that very much are the memories and the people I've met along the way."
Watson's time in the interview room wasn't without a little controversy.
Asked to reflect on last year's Ryder Cup defeat and the ensuing criticism from U.S. team member Phil Mickelson in its aftermath, Watson didn't pull any punches.
"That was a disappointment to me," he said. "Phil was very disappointed about not being able to play. It was just kind of sour grapes. That's understandable, and we just got waxed, the whole team, and the disappointment was just there."
As for his relationship now with Mickelson, Watson maintained, "We're cordial. I saw him [Tuesday] night, we said hello and, yeah, we're fine."
Watson: St. Andrews is a fitting place to end my career
Tom Watson has heaped praise on the Open Championship, as he looks to say an emotional farewell to the competition