Dallas Cowboys starting defensive lineman Mark Walen...

Dallas Cowboys starting defensive lineman Mark Walen will miss the 1989 season after undergoing arthroscopic surgery on his left knee, a team spokeswoman said.

Walen, a third-year veteran from UCLA, was reported in good condition at Mary Shields Hospital in Dallas. Dr. Robert Vandermeer repaired a torn interior cruciate ligament and damaged cartilage in Walen’s knee.