McGee took all the practice snaps with the starting offense while Jon Kitna sat out due to a strained left oblique. Kitna, the starter since Tony Romo suffered a season-ending broken collarbone Oct. 25, said he does not feel like he's progressed much in his recovery since suffering the injury in the second quarter of Saturday's loss to the Arizona Cardinals.
The Cowboys are still holding out hope that Kitna will be able to start Sunday's season finale against the Philadelphia Eagles. Kitna said he thinks he needs to be able to practice by Friday to be able to play in Philadelphia.
"It's a day-to-day thing," interim coach Jason Garrett said. "We'd like to think he's improving and we'd like to get him out on the practice field before the game."
At this point, Kitna can't throw a football with any force. The strained oblique, a muscle by the rib cage, prevents Kitna from creating the torque needed to get decent velocity on his passes.
"It's just certain movements," Kitna said. "Right now there's no pain just standing here. There's a dull sensation to it, but certain movements feel like you've got a knife in your side."
McGee, a 2009 fourth-round pick out of Texas A&M, had taken three first-team practice repetitions in his career before this week.
However, he played relatively well in his NFL debut last week, completing 11 of 17 passes for 111 yards without committing a turnover. McGee's 37-yard touchdown pass to Miles Austin, a perfectly thrown deep ball just over the outstretched hands of Cardinals safety Rashad Johnson, gave the Cowboys a lead with less than two minutes remaining.
McGee considers Kitna to be a great mentor and said he hopes the veteran will be able to play Sunday. However, McGee acknowledged that he's excited and eager about the chance to be the starter.
"This is my dream job, playing quarterback in the NFL and especially with the Dallas Cowboys," McGee said. "I'm having a blast. I'm just [going to] continue working on getting better this week, make strides and of course be ready to go Sunday."
"I was encouraged with how Stephen did," Cowboys owner Jerry Jones said of the Arizona game. "I must say, I was pretty impressed to have McGee come in, having not played at all, under those circumstances, and see our team keep going and competing. That's pretty impressive."
McGee grew up in the Central Texas town of Burnet, throwing passes to Bengals rookie Jordan Shipley on a team coached by Shipley's dad. They played for state titles as juniors and seniors.
At Texas A&M, McGee left higher on the school's career list for yards rushing by a quarterback (third) than for yards passing (fourth). He hardly played as a senior, though, getting hurt and then unable to get his job back. Still, Dallas drafted him in the fourth round. He was inactive all of last season and remained on the sideline this season until Kitna went down Saturday.
McGee's immediate concern was making sure he took the first snap cleanly. Garrett's advice: "It's just like Burnet, Texas. Just go play."
"He came into a difficult situation last week and played well," Kitna said. "This week isn't going to be any easier because he got a half of a game in last week. It's a learning process in this league to play any position, certainly to play quarterback. ... Regardless of how this week ends up, he's on the right track to be a good player in this league for a long time."
The team's reluctance to give him a shot didn't affect McGee's enthusiasm. A devout Christian, he believes his patience will be rewarded.
Perhaps as soon as this weekend.
"I've never questioned coaches or decisions that are out of my control," McGee said. "Every chance you do get is a huge opportunity. You send that video out to the whole league. Everybody sees it, everybody takes notice. It's basically a resume for the NFL. It's definitely an opportunity that if I do get, I want to make the most of and show people what I can do."
Tim MacMahon covers the Cowboys for ESPN Dallas. You can follow him on Twitter. Information from The Associated Press was used in this report.