Phil Mickelson is doing "great" after undergoing umbilical hernia surgery last month, according to Golf Digest's Tim Rosaforte. Mickelson had the procedure done on Oct. 19, three days after finishing T-8 in the Safeway Open, the first event of the 2016-'17 PGA Tour season.

"It wasn't an outie belly button per se, it just looked like it," Mickelson told Rosaforte. "It was a walnut-sized hernia behind my belly button. It was no big deal, nor did it affect me when I played. I pushed it back in every minute or so. I couldn't work out as intensely as I wanted to. That's all. It didn't hurt or affect me. It was just annoying."

Mickelson added, "it's why my belly button stuck out of my shirt all year." But that he's "all fixed up" now as the 46-year-old says he's ready to start his off-season workout program.

Mickelson is coming off a strong 2015-'16 season in which he had six top-five finishes on the PGA Tour, including a runner-up to Henrik Stenson at the Open Championship. He also helped the U.S. to its first win at the Ryder Cup in eight years, finishing with a 10-birdie performance in his Sunday singles match against Sergio Garcia.

If you're looking for a potential place for Mickelson to return to competition, he has made the CareerBuilder Challenge his first event in each of the past two years. Earlier this year, Mickelson replaced Bill Clinton as ambassador for the event, which will be held Jan. 19-22, 2017.

RELATED: How Phil Mickelson's Ryder Cup gamble paid off for the U.S.


WATCH: GOLF DIGEST VIDEOS