Running back Ickey Woods suffered an injury to his right knee as the Cincinnati Bengals participated in the first day of contact drills at Wilmington, Ohio.
Woods was taken back to Cincinnati for testing. Coach Sam Wyche said that the initial diagnosis was that Woods stretched a ligament.
All-Pro defensive end Bruce Smith of the Buffalo Bills underwent knee surgery for the second time in two years and will be out for the exhibition season and perhaps longer.
Dr. James Andrews removed cartilage chips from Smith's left knee and smoothed the surface of the knee bone in the operation at Birmingham, Ala. No ligament damage was found.
The previous operation was on Smith's right knee.
Veteran safety Mark Murphy could be sidelined for two weeks after separating a shoulder in the Green Bay Packers' first scrimmage.
Jim Harbaugh ended his holdout with the Chicago Bears and came to training camp with a new two-year contract for $2.5 million, but veteran Jim Covert, a two-time Pro Bowl offensive tackle, has a ruptured disk that probably will sideline him for the entire 1991 season and could spell the end of his NFL career.