CAMBRIDGE, Mass. — In late July, John Urschel reported to NFL training camp, just like about 2,800 other players across the league. Urschel checked into the Baltimore Ravens’ hotel, dropped off his bag, and then went to the team facility, where he sat through a full team meeting and an offensive line session. His mind wandered as the coaches went on about goals for the season and what they’d be working on at practice the next day. As a backup offensive lineman, Urschel would be rotating in at center and have to fight all camp just to make the team.