FRISCO -- Cooper Rush will play his final game of the year Thursday.Or so the Cowboys hope.The reserve quarterback is expected to start the preseason finale against the Tampa Bay Buccaneers at AT&T Stadium. As likely more than 30 Cowboys teammates skip this exhibition, the evening offers Rush the chance to cap an offseason during which he's cemented himself as quarterback Dak Prescott's primary backup for 2019.Prescott can wear a ball cap, eat sunflower seeds and joke on the sideline.Not Rush.