The Portland Timbers announced today that forward Jose Adolfo Valencia underwent successful surgery Monday afternoon to repair damaged cartilage in his left knee.

The procedure was performed by Timbers Director of Medicine Dr. Jonathan E. Greenleaf at Sports Medicine Oregon in Tigard, Ore.

Valencia, 20, is expected to miss 6-12 months. He will be placed on the Timbers' Disabled List while rehabilitating from surgery and will conduct his rehabilitation with the Timbers medical and athletic training staff in Portland.