NAPA (AP) — Second-round pick Menelik Watson’s first practice of training camp lasted less than 30 minutes Wednesday before the Oakland Raiders’ offensive lineman left the field after re-injuring a calf muscle in his left leg.Watson, the 42nd overall pick and projected backup to right tackle Khalif Barnes, had been on the non-football injury list since the beginning of camp after injuring his calf in mid-July.The 6-foot-5, 315-pound tackle jogged out to practice and took part in two offensive linemen drills before aggravating his injury. Watson angrily walked off the field with head trainer H.Rod Martin, punched a wooden bench near the team’s weight room and let out a scream before going into the locker room.A few minutes later Watson sat on the ground in the shade just outside a door of the locker room, his head down in obvious disappointment.“This is not the way I planned on my first training camp, I’ve not even took a snap yet,” Watson said. “It’s very frustrating, especially after the spring, making good strides in the spring.