FRISCO, Texas — As the Dallas Cowboys prepare for their season opener against the Carolina Panthers on Sept. 9, the health of two of their top offensive linemen is of paramount importance.

Pro Bowl right guard Zack Martin said his injured left knee suffered Saturday against the Cincinnati Bengals is feeling better, but Pro Bowl center Travis Frederick is seeking more opinions because of an issue with stingers that has kept him out of practice the past week.

Martin was initially concerned that he suffered a serious injury but said that once the initial pain wore off, “I knew I was fine.” Martin, who has not missed a game in his career, said he escaped any ligament damage to his knee and has only a bruise. He wore a small sleeve on his knee as he watched his teammates practice Monday at Ford Center at The Star. He played 35 snaps in two preseason games, which he believes is enough for him to be ready for the Panthers.

“Obviously, you never want to be out, but if you had to pick, this would be the time of the year,” Martin said. “As long as I’m ready to roll for Week 1, it’ll be good.”

Last week, Frederick visited specialist Dr. Robert Watkins in Los Angeles while the Cowboys were in Oxnard, California, for camp. Frederick said then that Watkins assured him he was not suffering from anything more severe than the stingers.

Like Martin, Frederick will not play for the rest of the preseason. Under head coach Jason Garrett, the Cowboys have played their regulars into the third quarter of the third preseason game and not played them at all in the preseason finale.

Frederick said the weakness that comes from the stingers can vary in length.

“A lot of it has to do with preventing it from happening again,” Frederick said after the Bengals game. “Even though you might be back to full-strength, you want to make sure the swelling is gone to prevent another one where that weakness comes back.”

Given the injuries to Martin and Frederick, as well as projected starting safety Xavier Woods (hamstring), Garrett is not sure if he will follow the same preseason plan for playing time. Receivers Cole Beasley (groin), Tavon Austin (hamstring) and Deonte Thompson (Achilles) did not practice Monday as they deal with injuries. Owner and general manager Jerry Jones said he thought Ezekiel Elliott, who did not see action in the first two preseason games, would be ready to play in the regular season without any work.

“In regards to playing guys in the preseason, it’s always a balancing act,” Garrett said. “It always has been about how much you play guys to get them ready for the season vs. putting them in a situation where they expose themselves to injury. We believe it’s important to play guys at some point in the preseason to get them ready for regular-season action. We feel like they’re more compromised in the regular season if they don’t play at all in the preseason. Now, you take each of the cases independently, and certain positions need to play more in the preseason, certain positions need to play more together in the preseason, certain positions probably need to play less.

“It changes from year to year. It changes from guy to guy and position to position. We certainly don’t want to put anybody out there to expose them to injury. The objective of playing guys in preseason games is to get them ready for the regular season.”