Oregon will play two games in Madrid and one each in Valencia and Barcelona before returning home on Aug. 31. Ducks coach Dana Altman was noncommittal on when Brooks would return to the lineup.
"He's going to be out for a while," Altman told The Oregonian. "He had surgery and we'll just have to wait and see what the doctors say."
Brooks averaged 16.7 points, 5.4 rebounds and 3.1 assists last season as a sophomore. He entered his name in the NBA draft after helping Oregon win its first Pac-12 regular-season title since 2002 but decided to return to school for his junior year.
Brooks is a big reason the Ducks earned a No. 1 seed in last season's NCAA tournament and likely will be ranked in the top 10 when the season begins. Until he comes back, the Ducks will rely heavily on guard Tyler Dorsey and forward Chris Boucher, who return this season.