ASHBURN, Va. -- The Washington Commanders will be without corner Marshon Lattimore once again, but they remain optimistic about his return this season.

Coach Dan Quinn on Friday ruled out Lattimore along with two other players for Sunday's regular-season finale at Dallas. The Commanders (11-5) can clinch the sixth seed in the NFC playoffs with a win over the Cowboys (7-9). Dallas will be without leading receiver CeeDee Lamb, sidelined with an AC joint injury.

Lattimore reinjured his left hamstring in his second game back with Washington, a 36-33 win over Philadelphia on Dec. 22. He already had missed five games with the injury, including four after the team acquired him in a trade with New Orleans.

Quinn said, after watching Lattimore on a side field, "I love the speed he's working with and he's certainly very close."

The coach said he wasn't sure about the long-term impact of the hamstring injury, though he added that there would be routine maintenance to try to make sure Lattimore is fine.

"I do know he's working incredibly hard at it," he said. "When you're close you want to obviously go for it. And the fact that he is putting in all the work to go there, I'm hopeful that it'll eventually be OK."

Washington also ruled out two backups who have been key special teams players: safety Tyler Owens and linebacker Jordan Magee.

The Commanders are deciding whether to activate running back Austin Ekeler from injured reserve. He has missed the past four games after suffering a concussion, and the team opened the 21-day window for his return Wednesday.