IRVING, Texas -- Most teams use the third preseason game as a dress rehearsal for the regular season and play their regulars for at least a half if not into the third quarter.
Tight end Jason Witten (spleen), wide receivers Miles Austin (hamstring) and Dez Bryant (knee) and center Phil Costa (back) will not play against the Rams because of injuries. The defense will celebrate the returns of linebacker Anthony Spencer (hamstring), defensive end Jason Hatcher (hamstring) and nose tackle Jay Ratliff (foot), but its best player, linebacker DeMarcus Ware, will not play because of a hamstring injury.
Quarterback Tony Romo will start and have four-fifths of the expected offensive line in front of him with guard Nate Livings' return from a hamstring injury, but running back DeMarco Murray will be the only starting skill player around him.
"If things go well, they might play less," Garrett said. "If things don't, they might play more."
In reality, Saturday's game against the Rams might more closely mirror a regular-season game because of the need to replace injured players.
Go back to the 2011 regular-season finale at the New York Giants. Seven players who weren't on the roster at the start the season played starting or significant roles on offense, defense and special teams in that game.
"Ideally, before you start your OTAs in the offseason you say, 'This is my starting 11 on offense. This is my starting 11 on defense. These are the starting 11s in every situation on our team. You guys go play together for 10 OTAs, for minicamp and all throughout training camp,'" Garrett said. "That's just not realistic."
Injuries happen in the NFL. Teams have to change starting lineups, tweak the backup plans and alter game plans throughout the regular season.
The Cowboys' injuries piled up once the pads came on in training camp.
Austin will not see a snap in the preseason for the second straight summer. Witten will have fewer than 10 snaps of preseason action. Bryant has a case of patella tendinitis that should not be a problem for the Sept. 5 season opener, but he is hardly a finished product. Costa might be the only starter on offense to play in the last preseason game, Wednesday against the Miami Dolphins.
Ware's preseason action came to an end when his hamstring tightened up. No need to rush the NFL's premier pass-rusher back, especially when he was as dominant as he was in camp. The first snap cornerback Mike Jenkins sees will come in a regular-season game because of offseason shoulder surgery.
Saturday's game will be about the understudies. Again.
Can undrafted rookie wide receiver Cole Beasley fill a role on the offense? Who else fills out the backup receiver spots? Can James Hanna handle all of the tight end business? Can Sean Lissemore really push for a starting defensive end job? Who fills out the final linebacker spots?
The good part is they will go against the Rams' regulars, not just the backups, to give them a better test to see what and how much they can handle.
Sometimes, players fighting for a roster spot complain about a lack of opportunity to make a 53-man team when they are shown the door. There can be no complaints this summer.
"It does provide an opportunity for other young players to step up and show us what they can do," Garrett said. "A lot of guys have done that throughout training camp and they've shown us, 'Hey, I deserve to be on this team,' or, 'I deserve this particular role on this team.' It allows us as coaches to evaluate them that much better and that much more. They've been in practice situations and probably played a little more in the preseason games than they would have otherwise. All in all, it's good for your football team."
The Cowboys won't know just how good it will be for them until later in the season.