Cowboys enter training camp with questions at linebacker, running back, and offensive line

Cowboys training camp begins this week, the first practices of the season
Key storylines include roles for talented receivers CeeDee Lamb, Michael Gallup, and Brandin Cooks
Tony Pollard expected to lead running game but exact roles uncertain
Offensive line has openings at left guard and potential position changes
Linebacker depth a concern behind starters Vander Esch and Parsons