Among the former Texas A&M quarterbacks facing each other in the preseason finale, Ryan Tannehill already knew he was going to be the first-ever rookie starter for the Miami Dolphins.

Stephen McGee might have taken his last snaps for the Dallas Cowboys, even though his team won 30-13 Wednesday night.

Tannehill, the Dolphins' first-round pick this year, was 5 of 7 passing for 35 yards playing the first two series in his final tuneup before their opener Sept. 9 at Houston. Miami (0-4) was winless in the preseason, with Tannehill starting the last two.

"We realize that we have a long way to go and have a lot of work to do," Tannehill said. "But we're excited about the opportunities that we have. Everyone gets a clean slate going into the regular season."

Tannehill, first-year coach Joe Philbin and the Dolphins have some extra time before opening their regular season.

The Cowboys (3-1) finished the preseason a week before playing in the NFL's kickoff game against the defending Super Bowl champion New York Giants. They kept quarterback Tony Romo and their front-line starters standing on the sideline.

Lance Dunbar ran 15 times for 105 yards, including a 58-yard touchdown in which he made several Miami defenders miss. Linebacker Orie Lemon returned an interception 26 yards for a score and Phillip Tanner, who started at tailback with DeMarco Murray and Felix Jones sitting out, had a 1-yard score while carrying nine times for 48 yards.

McGee, a fourth-round pick from A&M in 2009, was 9 of 18 for 124 yards in the first half. He had completions of 32 and 36 yards to set up Tanner's score.

"He did a good job once we got going a little bit on offense," coach Jason Garrett said. "You could see him get a little bit more comfortable, get a little rhythm."

Two years ago in another preseason finale against the Dolphins, McGee passed for 304 yards while going all the way in the victory that probably assured him the spot as the team's third quarterback that season. But he has played in only three regular-season games with one start.

With Kyle Orton signed during the offseason to be Romo's backup, Dallas likely will carry only two quarterbacks on its 53-man roster that has to be set by Friday evening. Plus, McGee is no longer eligible for the practice squad like Rudy Carpenter (4 of 10 for 48 yards) would be.

"We value the quarterback position and we want to allocate the necessary resources to it," Garrett said. "Having said that, you have to manage the rest of your roster and injures sometimes are a factor."

The Cowboys said after the game that former Pro Bowl cornerback Mike Jenkins, who missed the entire offseason and preseason recovering from shoulder surgery, passed his physical earlier Wednesday. That means Jenkins could practice Saturday and possibly play against the Giants.

Pro Bowl receiver Miles Austin didn't play in the preseason because of hamstring issues, and receiver Dez Bryant was held out for the second straight game because of right knee tendinitis. Both are expected to be ready for the Giants, though Pro Bowl tight end Jason Witten (lacerated spleen) is less certain for the unprecedented Wednesday opener.

Lamar Miller had 17 carries for 60 yards for the Dolphins. His 1-yard TD capped a 14-play, 89-yard drive that took exactly half of the third quarter to complete.

Dan Bailey kicked three field goals for the Cowboys while Dan Carpenter had field goals of 21 and 53 yards for Miami less than 2 minutes apart late in the first quarter.

After Carpenter's shorter kick, Teddy Williams fumbled the ensuing kickoff at the Cowboys 33. That's when Matt Moore took over for Tannehill.

Moore was only 4 of 12, including the pass over the middle early in the second quarter that Lemon picked off and took into the end zone for a 10-6 lead.

"Obviously, it's a disappointing loss," Philbin said. "I just told the team I don't care if it's the fourth preseason game, the seventh regular-season game or the Super Bowl, that's unacceptable. ... Not a good performance by our team."

NOTES: Dallas CB Lionel Smith sustained a concussion, and OL Daniel Loper tweaked a hamstring. ... Derrick Dockery started at left guard for Dallas, and got in a few plays before leaving to catch a flight to Washington, D.C., to attend a family funeral.