The surgery was on Wednesday and took place in Vail, Colo.
It was known beforehand that the Spaniard needed to have his ACL reconstructed. But it wasn't until after the surgery that the team announced that his LCL needed to be reconstructed, as well.
Rubio, who will miss the rest of the season, was tops among NBA rookies in assists with 8.2 per game when he went down with 16 second to play in a March 9 game against the Los Angeles Lakers. Rubio was also also fifth among rookie scoring, averaging 10.6 points per game.
The Timberwolves are just 2-5 since Rubio's injury, including Wednesday's 116-100 loss to the San Antonio Spurs.