The move was made so the team could sign tight end Colin Cochart.
McGee, a former Texas A&M quarterback, had been with the team since 2009.
Cochart, 6-foot-4, 258 pounds, had been released by the Cincinnati Bengals.
The 25-year-old played in 10 games for the Bengals last season, catching five passes for 44 yards.
With seven-time Pro Bowl tight end Jason Witten still questionable while recovering from a lacerated spleen, Cochart provides some extra depth at that position. Cochart started three games as a rookie last season.
The Cowboys are not required to release a practice report until Sunday so it's not known how much work Witten, Austin and Bryant received.
Bryant, however, was wearing a sleeve on his right knee and all the players were in full pads.
Mike Jenkins (shoulder) was supposed to practice on Saturday, but during the open media portion of practice, he wasn't on the field. He could have gotten some work in the walkthrough session or was getting some rehab work done inside the facility.
Fourth-round pick Kyle Wilber (hand) was in full pads, but he was wearing a small cast during the special team drills.
Before McGee was released, coach Jason Garrett had praised the backup quarterback when asked why he remained on the roster.
"We like Stephen, we like what he's done and we evaluate the quarterback position," Garrett said. "What we try to do is try and manage the roster as best we can. We want to keep good players. At the same time we understand that we have to manage the different injury situations that we have particularly early on in the season.
"We're not unlike 31 other teams, everybody is doing these kinds of things and how we make hard decisions. I thought Stephen had a good preseason and a good training camp. We like having three quarterbacks on the roster."
McGee had played in three NFL games completing 56.1 percent of his passes for 420 yards with three touchdowns and no interceptions.
He made only one start, the 2010 regular season finale at Philadelphia.
McGee became the 35th different quarterback to start a NFL game for the Cowboys. He completed 11 of 27 passes for 127 yards with one touchdown in a 14-13 victory.
Dallas also had a full eight-man practice squad in place and on the field Saturday. That group included rookie receiver Danny Coale, the injury-hampered fifth-round pick who was left off the 53-man roster at Friday's deadline.
Information from The Associated Press was used in this report.