Milwaukee Bucks forward Giannis Antetokounmpo has had surgery on his left knee, the team confirmed Wednesday, leaving the basketball star's participation for Greece in August's FIBA World Cup in doubt.

"He had a routine surgery on his left knee, and it went great," Bucks head coach Adrian Griffin said on Wednesday.

"Everything went as planned, and we expect him back ready to go in training camp," he added.

The Bucks are expected to begin their camp in early- to mid-September with the World Cup starting on August 25 and running until September 10.

The Athletic cited a league source as saying that Antetokounmpo's availability for Greece is "in question" after what it described as surgery to "clean up loose cartilage in his left knee."

The two-time NBA Most Valuable Player suffered a back injury during game one of the Bucks's first-round playoff series against the Miami Heat and did not return until game four. The Bucks, the number one seed in the East, were upset in five by Miami in the best-of-seven series.

The World Cup will be held in the Philippines, Japan and Indonesia.

Greece has been drawn in group C with the United States, New Zealand and Jordan.

Losing Antetokounmpo would be a huge blow to Greece's hopes in the tournament.

He was top scorer in last year's EuroBasket tournament, averaging 29.3 points although his team went out in the round-of-16 to the Czech Republic.

Antetokounmpo was part of the Greece team at the 2019 World Cup which failed to get out of the group stage.

The 28-year-old's older brother and Bucks' team-mate Thanasis, is also part of the Greece squad along with his younger brother Kostas, who plays for Greek club Panathinaikos.