Bryant's status for the three-day minicamp that begins Friday is in doubt.
For the second consecutive day, the team's first-round pick did conditioning drills off to the side under the supervision of associate athletic trainer Britt Brown during the voluntary practice. Bryant did not participate in team drills Tuesday after feeling tightness in the hamstring.
Bryant and head coach Wade Phillips described Tuesday's rest as a precautionary measure.
Bryant, whom the Cowboys selected with the 24th overall pick after trading up three spots, missed another OTA workout two weeks ago because of a stomach virus.
Tim MacMahon covers the Cowboys for ESPNDallas.com You can follow him on Twitter.