Gasol had not played since March with what was initially categorized as a left ankle injury.
Despite playing without the services of Gasol, the Bucks swept the Detroit Pistons in the first round of the playoffs and beat the Boston Celtics 4-1 in the second round. They now await the winner of the series between the Toronto Raptors and Philadelphia 76ers.
The 38-year-old Gasol reached a buyout agreement with the San Antonio Spurs on March 1, which ended his three-season tenure with the team.
After the buyout, Gasol came to terms on a contract with the Bucks. Gasol appeared in just three games for Milwaukee before getting injured, averaging 1.3 points and 3.3 rebounds.
In 30 games on the season, Gasol averaged 3.9 points and 4.6 rebounds per contest, which was by far the lowest production of his 18-year career.
Gasol has essentially seen and done it all in the NBA with six All-Star nods and two championships to his credit. Also, his career averages of 17.0 points, 9.2 rebounds and 3.2 assists over 1,226 regular-season games make him one of the most consistent and productive bigs of his era.
With Gasol out, Brook Lopez will continue to see the lion's share of the playing time at center for the remainder of the playoffs. Ersan Ilyasova is the primary backup at center, although he is more comfortable as a power forward, meaning head coach Mike Budenholzer doesn't have much to fall back on beyond Lopez.
The Bucks announced that Gasol should be healthy in time for training camp, but since his contract expires at the end of the season, there is no guarantee that he will be back with Milwaukee.
If Gasol plans to continue playing beyond this season, then the diagnosis bodes well for his chances of being able to compete in his 19th NBA campaign.