Olson injured his left knee in U.C.L.A.'s bowl game last season and, after ligament surgery, was not even sure if he would play this season.
Bill Pulsipher underwent season-ending ligament surgery last April.
He was given hardship discharge because of cruciate ligament surgery.
Bavaro has undergone ligament surgery on his left knee twice in the last year.
Mark Bavaro, who underwent ligament surgery on his left knee in January, went through his first contact work today at the Giants' training camp.
Anterior cruciate ligament surgery is a complex surgery that requires expertise in the field of sports medicine.
On 19 February it was declared that he would be out for the rest of the season after the cruciate ligament surgery.
Then, in 1995, he developed an elbow problem, had ligament surgery on his right elbow and missed more than a season.
One of the league's best pass rushers, Keith Millard, was lost for the season after ligament surgery on his right knee.
The rehabilitation period for reconstructive ligament surgery generally is nine months to a year.
