Portland Trail Blazers big man Zach Collins underwent his second left ankle surgery in four months on Wednesday and will be sidelined indefinitely.

The Trail Blazers termed it as a “revision surgery” to repair a stress fracture of the medial malleolus.

On Sept. 1, Collins underwent surgery for a hairline fracture of the medial malleolus. He was injured during the NBA play-in game against the Memphis Grizzlies on Aug. 15, leaving after playing just seven minutes.

Collins played in just 11 games last season and averaged 7.0 points and 6.3 rebounds. He missed 4 1/2 months due to a dislocated left shoulder.

The former first-round pick out of Gonzaga has career averages of 5.7 points and 4.0 rebounds in 154 games (12 starts) over three seasons.