SAN FRANCISCO -- Defensive linemen Justin Smith is the most notable 49ers player not in uniform for Friday's opener against the Minnesota Vikings.Smith, the winner of the Bill Walsh Award last season as the team MVP, is likely being given the night off. He was on the field during pregame warmups, but is not injured. He sat out a practice last week but returned the next day, as coach Jim Harbaugh gave the veteran a rest day.Other players not expected to see action Friday night are tight end Nate Byham, defensive lineman Will Tukuafu, receiver Joe Hastings and linebacker Cam Johnson. Linebacker Darius Fleming (knee) and running back Jewel Hampton (bone spurs) have yet to be activated for training camp.The 49ers announced that defensive lineman Demarcus Dobbs would be listed as a tight end and wear No. 40. However, Dobbs took part in warmups with the 49ers' defensive linemen. He is expected to see action on both sides of the ball during the exhibition season. Prior to Friday's game, Parys Haralson yelled a greeting to former 49ers coach Mike Singletary, now the Vikings' assistant to the head coachlinebackers. Larry Grant went over to shake Singletary's hand during pre-game warmups.