One recent morning at Redskins Park in Ashburn, linebacker Robert Henson arrived early and spotted him in the lobby, the man known around NFL teams as the Turk. He held a clipboard, but it might as well have been a scythe.

Quick smile. Eyes down. Keep walking.

"I was just thinking, 'Uh-oh,' " said Henson, a rookie out of Texas Christian. "He wasn't there for me. But that's when it really hit me, you know, that there are some good guys who aren't going to be a part of this team."

Thursday's game at Jacksonville provides a final opportunity for bubble players such as Henson to prove their worth to coaches. Seventy-five players will be on the roster at the start of the game. By Saturday night -- the deadline across the league for team's to shrink their rosters to 53 -- nearly one-third of them will be looking for work.

While coaches try to envision the regular-season depth chart, they say several players' fates could swing on their performances against the Jaguars.

Henson is battling on the same bubble as Cody Glenn, Darrel Young and Chris Wilson for just one or two available linebacker spots. Colt Brennan and rookie Chase Daniel will split quarterback duties Thursday night, and only one likely will remain on the team through the weekend. Similarly, kickers Dave Rayner and Shaun Suisham enter the final round of their five-week tug-of-war for a single roster spot.

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And with Clinton Portis among several starters not expected to play, young running backs such as Marcus Mason, Anthony Alridge and Dominique Dorsey have a final opportunity to present their respective cases.

For the second preseason in a row, Mason has wowed fans. He leads the team with 87 yards on 25 carries through three preseason games. He scored the team's first touchdown against the Patriots last week, and after the game said he had 15 missed calls from family and friends excited about his performance. While he didn't earn a roster spot a year ago, his best bet is if the Redskins choose to carry five running backs instead of four. Returning backs Portis, Ladell Betts, Rock Cartwright and Mike Sellers all have some job security.

"It's all on this one game," Mason said. "It's worse as a young guy because you know you'll be in the game all night. You have special teams, then you have offensive or defensive reps. So it's very tiring.

"But you know that every play is like a job interview. You have to ace every single one of them."

Most bubble players know the numbers. They realized there weren't 53 job openings at the start of camp. In truth, there were only a handful of open positions -- and three dozen players eager to show off their qualifications. If the team chooses to keep 25 offensive players and 25 defensive players (in addition to a punter, kicker and long snapper), that bodes well for a player such as Mason or Alridge. Twenty-five on offense likely means three quarterbacks, three tight ends, five receivers, nine linemen and five running backs.

Coaches say they enter the preseason finale with an open mind, hoping a player or two will make a convincing argument.

"Maybe you just get a confirmation: 'You know what? I was right about this guy.' Or, 'You know what? Now maybe he'll perform in a different way in a different level, high or low,' " Coach Jim Zorn said. "That will change the complexity of it as well."

A season ago, Brennan saw his stock rise with each preseason game. This year he entered camp poised to challenge for the backup quarterback job. Entering the preseason finale, he instead finds himself tap dancing on the bubble, fighting for roster survival. It's a position with which Brennan says he's comfortable.

"Even after a lot of good preseason games, you don't know," Brennan said of the uncertainty that followed his rookie training camp. "It's the same as this year. No matter how good or bad you do, you really never know. You don't know how much they look into something, what they're really judging, the criteria they judge you by. So there's always pressure."