MINNEAPOLIS -- This is it for the Dallas Cowboys. It's the final dress rehearsal before the games become real starting with the Sept. 11 season opener at the New York Jets.Thus, tonight's preseason game against the Minnesota Vikings will feature the starters playing the entire first half and possibly into the third quarter.The Cowboys have game-planned the Vikings, a first for the preseason, and will be looking to put together a complete performance.Of course, it will be difficult because of the missed off-season due to the lockout and the remaining work in progress on defense in its attempt to learn Rob Ryan's new scheme."I think our defense, like our football team, is a work in progress," coach Jason Garrett said. "The more difficult thing for our defense is the defensive system was not in place last year like our offense and kicking game systems have been in. I think they've responded very well and I think it's a tribute to our coaches."Here are five storylines to watch tonight:1Murray's debutRookie running back DeMarco Murray will be making his preseason debut after being sidelined since the start of the camp with a hamstring injury. The Cowboys consider him an all-around back who can catch the ball out of the backfield and run with power and elusiveness in space. He was considered injury prone at Oklahoma. This is his chance to put any health concerns aside.2Third receiver jobReceiver Kevin Ogletree remains under scrutiny in his bid to be the Cowboys' third receiver. He will start for the second consecutive game in place of the injured Miles Austin and needs to make his presence felt. Wide receiver coach Jimmy Robinson said nothing has been decided. If Ogletree doesn't prove himself beyond a doubt, the Cowboys could be searching for a third receiver on the waiver wire.3Nagy's presenceRookie seventh-round pick Bill Nagy will get his second consecutive start at left guard. He has acquitted himself well so far. With veteran Montrae Holland expected to work back into practice next week, this could be Nagy's last chance to show that he is worthy of keeping the starting job. All in all, it's been quite a run for Nagy, who was not a regular starter at Wisconsin but is now in the running to start for the Cowboys.4Offensive rhythmQuarterback Tony Romo has been hit and miss so far in the preseason and training camp as he tries to work off the rust after missing the last 10 games in 2010 with a fractured collarbone. He and the first-team offense did not have a good week of practice and needs a good effort against the Vikings to build some confidence for the regular season. A clean performance by Romo and a little pitch and catch with Dez Bryant would go a long way toward easing any concerns.5Ryan's schemeWith 10 of 11 starters back from last year's defense that was among the worst in team history, the Cowboys are counting on coordinator Rob Ryan's new scheme to make the biggest difference in 2011. The first two preseason games have featured a plethora of communication breakdowns and busted assignments. Ryan says don't worry, things will be fine. It would be easier to accept if they show more progress against the Vikings.