IRVING — The Dallas Cowboys’ defensive line is getting closer to full strength with the season opener against the San Francisco 49ers coming up on Sunday.Defensive tackles Henry Melton, returning from an anterior cruciate ligament injury in his left knee as well as a groin injury that slowed his progress in training camp, and Terrell McClain, who has been sidelined for a month with a high ankle sprain, practiced Monday and are expected to play.So is left defensive end George Selvie (shoulder), although he didn’t practice Monday.Still, having Melton and McClain practicing together after neither played in the preseason are positives for a line that has been depleted by injuries.“Guys are getting healthy,” veteran end Jeremy Mincey said. “It’s good to have the presence of all the guys who are going to be here. We’re just focused on getting better every day.”The number of snaps players such as Melton and McClain will be able to handle in the opener remains to be seen.The Cowboys are expected to rotate several linemen into the game. However, Melton is viewed as the key piece on the line as the three-technique tackle.“I feel good, I’m excited,” Melton said. “We’re still building. The chemistry is going to take a little bit of time.”But at the end of the day, Melton is optimistic with everyone healthy.“There are a lot of guys that people haven’t heard about that they’re going to hear about,” he said. “There are going to be a lot of guys out there that are going to be making plays.”Vaughan earns spotDustin Vaughan showed a big arm and upside in the preseason, which convinced the Cowboys to keep him as their third quarterback. They didn’t want to risk losing him by exposing him to waivers.“I’m honored and blessed to have this opportunity to play for the Dallas Cowboys, and hopefully it continues,” said Vaughan, an undrafted free agent out of West Texas A&M. “Hopefully I have a long future with these guys.” Vaughan didn’t think of himself as a long shot.“No,” he said. “I thought I could handle it and I thought I could make it. That’s the attitude you need to have and you need to have that kind of confidence.”Vaughan got the second-most snaps in the preseason, behind backup Brandon Weeden, completing 22 of 43 passes for 212 yards with one touchdown and no interceptions.“We feel Dustin has a lot of potential,” coach Jason Garrett. “We feel like he has a lot of really good traits. He’s a smart guy. He’s instinctive. He’s big, he can throw it. He just needs to play.”Two other undrafted rookies also made the team — cornerback Tyler Patmon from Oklahoma State and tackle Donald Hawkins from Texas. Patmon has been with the team, while Hawkins was acquired Sunday off waivers from Cleveland, which had picked him up from Philadelphia.“I have been playing with a chip on my shoulder since high school,” said Hawkins, who played high school and junior college football in Mississippi. “Making the transition to the NFL after being undrafted was definitely a chip, and after being cut twice, it just makes the chip even bigger. Play harder and thank God for being in the position I’m in right now.”Dixon cutThe Cowboys waived safety Ahmad Dixon, a seventh-round pick out of Baylor, on Monday to clear a spot for veteran C.J. Spillman.Dixon led the team in tackles the first preseason game; was benched for the second game because he was tardy to a walkthrough; and then drew a penalty and fine for an illegal hit during the third game against the Dolphins.Garrett did not say whether the Cowboys would be interested in Dixon as a practice squad player should he clear waivers.“We’re still formulating our practice squad right now,” Garrett said.In other roster moves: The Cowboys signed nose tackle-turned-fullback Nikita Whitlock, a Wake Forest and Wylie High School product, to the practice squad; they signed linebacker Korey Toomer, a 2012 fifth-round pick waived by Seattle; and they waived defensive back Jemea Thomas.
Drew Davison, 817-390-7760 Twitter: @drewdavison