Racing Positions49ers defensive end Aaron Lynch leaves practice with apparent injury8YNick WagonerO-line, backup QB among positions to watch as 49ers open preseason8YNick Wagoner49ers' Ray-Ray Armstrong takes turn with starters at weakside LB8YNick Wagoner49ers try to regroup after Donavin Newsom's scary injury8YNick Wagoner49ers rookie LB exits on stretcher after collision8YNick WagonerBrian Hoyer has strong practice despite facing constant pressure8YNick WagonerTwo cornerback jobs up for grabs as 49ers open camp8YNick Wagoner