Speaking to The Athletic's Sam Amick, Hayward had an elective and previously unknown procedure in early October "to alleviate persistent nerve pain in his left foot."
Hayward described the surgery as "pretty minor."
Hayward missed most of the Boston Celtics' playoff run last season because of a sprained right ankle. He suffered the injury in a 109-101 win over the Philadelphia 76ers in Game 1 of the Eastern Conference quarterfinals in August.
After sitting out four weeks, Hayward returned for the final four games of the Eastern Conference Finals against the Miami Heat.
When the season ended, Hayward declined his player option in his Celtics contract to become a free agent. The 30-year-old was coming off his best season with the team, averaging 17.5 points, 6.7 rebounds and 4.1 assists per game in 2019-20.
The Charlotte Hornets swooped in to acquire Hayward for four years and $120 million in a sign-and-trade deal. There was widespread criticism of the deal, but the early returns have been positive for the organization.
Hayward leads the Hornets in scoring (a career-high 22.2 points per game) and is shooting a career-best 40.9 percent from three-point range.
Despite a 6-8 record, the Hornets are in the middle of a crowded race for the top spot in the Southeast Division. They enter Friday one game behind the division-leading Atlanta Hawks.