IRVING, Texas – Heading into training camp, no position seemed to be more wide open than the defensive line group.

While there always seems to be an eight-to-nine-man rotation, just deciphering which players would end up making this squad was quite a feat.

As it turned out, getting the front-line players all on the field at once was a challenge, too. In fact, the Cowboys never got their top defensive linemen together for even one practice. And that's probably not going to happen for a while considering rookie DeMarcus Lawrence will miss at least another two months with a broken foot.

But there is somewhat good news at the position as the Cowboys get ready for the season opener Sunday vs. the 49ers.

 Not only did Henry Melton practice with the team again and is expected to start at the 3-technique defensive tackle spot, but Terrell McClain was also back on the field for the first time since the first week of training camp. McClain is expected to rotate at the 1-technique with Nick Hayden, who started all last year and has taken all of the first-team reps during camp and preseason with McClain out.

Also, while defensive end George Selvie spent most of Monday's practice on the conditioning cords, he said he fully expects to practice Wednesday despite a shoulder injury he sustained on Aug. 23 against the Dolphins.

"No, I'm definitely going," Selvie said, referring to the 49ers game. "But next practice I'll be there. I'm going this week. We're getting a lot of guys back. Henry came back, Terrell is coming back out. We're getting the chance to work together. It's been a long time."

Selvie said he doesn't anticipate wearing any harness or brace for his shoulder during practice or the game this week.

As for Melton, who suffered an ACL injury last season with the Bears and has also been slowed by a groin problem the last few weeks of camp, he's also eager to return, but said the team will continue to be smart in the snaps he receives.

"You know what, I'm just going to go with the flow," said Melton, who was held out of all four preseason games. "If they want to hold me to a certain amount of plays, I'm just going to listen to them. But, I feel good. I'm excited. It's going to be our first game-week. I'm excited and ready to go."

The Cowboys obviously need their best linemen when facing the 49ers on Sunday. Stopping the run is always the top priority for any defense, especially against a physical San Francisco team, which ranked third in the NFL last year in both yards (2,201) and attempts (505). Not only do the 49ers possess a strong attack that features veteran Frank Gore, who had 1,116 rushing yards and nine touchdowns last year, but one of the NFL's best running quarterbacks in Colin Kaepernick.

Head coach Jason Garrett said Kaepernick is dangerous with his legs, but that's only half of his game. [embedded_ad]

"I think he's like a lot of these quarterbacks who are really, really good athletes," Garrett said. "The thing you've got to remember about him is he really can throw the football. He's a big, strong guy who can throw it all over the park. If you give him lanes or you give him an opportunity to break contain, he can make huge plays with his feet. There's a point where he's just running by people. So much of what they've been able to accomplish offensively comes from his ability to throw it, his ability to make plays with his feet when things break down. He's a big part of what they do. They have a big, strong offensive line, they have a great runner, and they have a dynamic, playmaking quarterback. The challenges are there. They're all over the tape."

And that's why getting guys like Melton, McClain and Selvie back for this game couldn't be better from a timing standpoint.