Notably overlooked as a wildcard pick by U.S. captain Davis Love III despite being ranked seventh in the world, Watson was officially appointed as one of five vice-captains for the hosts ahead of this week's competition at Hazeltine National.
"Bubba has offered a couple times to come and be one of our assistant captains, and I told him we had an extra red cart and we'd love to have him," Love said during a joint news conference on Monday with his European counterpart, Darren Clarke.
"He adds a lot of fun, he adds a different personality, he brings a great heart."
Left-hander Watson joins Tiger Woods, Steve Stricker, Jim Furyk and Tom Lehman as assistants to Love.
Renowned for his booming drives and creative short game, Watson has played in the last three Ryder Cups and would have been the third-highest ranked American in their 12-man lineup if selected for the 2016 edition.
However, Love opted to discard the merits of a seven-times PGA Tour champion who has twice won the Masters, choosing Rickie Fowler, JB Holmes and Matt Kuchar as his first three wildcard picks before adding Ryan Moore as his fourth late on Sunday.
Moore earned the final selection after a red-hot run of form since the PGA Championship in July, highlighted by a victory at the John Deere Classic in August and a playoff loss to Rory McIlroy at the season-ending Tour Championship on Sunday.
"It was a tough decision," Love said of his final pick. "Bubba obviously disappointed not to be on the team.
"We waited until the last minute to catch a hot player, and Ryan week after week after week after week was the hottest player ... he's just been right there at the forefront for us. He's a great addition to our team. Obviously playing great."
Watson first presented his case to be an assistant after he was overlooked as one of the first three wildcard selections.
"And then he offers, if you don't pick me (on Sunday), I would like to be assistant captain, before he even played the Tour Championship," Love said.
"And then I called him and told him that I was going a different direction again, and he immediately said, 'I still want to be a part of this team, if you'll have me.' Incredible gesture."
(Editing by Frank Pingue)
