ARLINGTON — The final preseason game might feel meaningless with every big name on the sidelines. Don’t expect Tony Romo to take a snap with the Dallas Cowboys or Peyton Manning with the Denver Broncos. Dez Bryant and Demaryius Thomas will have front-row seats from their respective sidelines, too.But it’s a meaningful game for plenty of other players trying to secure spots on a 53-man roster. The Cowboys certainly have jobs up for grabs, as executive vice president Stephen Jones said, and will thoroughly evaluate the candidates throughout this game before making final cuts.1Henry MeltonHe’s on the team and expected to play an important role as the three-technique on the defensive line. But he has yet to take a snap this preseason. He had surgery last season after tearing the anterior cruciate ligament in his left knee in a Week 3 game and has been limited recently with a groin injury. Melton should get some snaps Thursday night in his Cowboys’ debut. His play this season will be one of the determining factors in whether the defense gets turned around.2QuarterbacksBrandon Weeden is Romo’s primary backup, and that is not going to change. He will play in this game, possibly the entire first half. The bigger question is rookie Dustin Vaughan, who is the Cowboys’ third quarterback after they released Caleb Hanie. Does Vaughan show enough to warrant a spot on the 53-man squad, or is the team poised to go with only two quarterbacks on the active roster again?3Offensive lineJerry Jones has stated multiple times since the Miami Dolphins game on Saturday that the offensive line could use more game action before the season opener. That might happen Thursday, although coach Jason Garrett and Stephen Jones would not commit one way or the other. Center Travis Frederick didn’t want to weigh in, either, saying: “I’m really glad I don’t have to make that decision.”4LinebackersThe Cowboys continue to search for their best three starting linebackers, and rookie Anthony Hitchens is making a run at being the first-team middle linebacker with Justin Durant and Bruce Carter on the outside. But the wild card remains Rolando McClain, and whether he proves to be a dependable player.5Winning Yes, it’s only the preseason, but the team does not want to go winless. It might not have much bearing on how the season plays out, but it would at least give them some momentum going into the Sept. 7 opener against San Francisco. “We play the games to win. There’s no question about that,” Garrett said. “Evaluations are most important, but certainly winning matters.” The Cowboys haven’t had a winless preseason since 2000, only the fourth time in their history they have failed to win an exhibition game.