Earnest Byner spent the past six years as the Baltimore Ravens' director of player development, cultivating relationships with young players, growing to care for them, then often having to say goodbye when they were released. Now, in his first season as the Washington Redskins' running backs coach, Byner is being confronted by a familiar uneasy feeling, knowing that several of the players he has worked so closely with over the past few months will be gone in a few weeks.

Pro Bowl tailback Clinton Portis is entrenched as the starter and Chad Morton surely will make the team given his kickoff and punt return skills. As Byner sees it, he has four other backs fighting for two spots on the final 53-man roster that will be set next month. Those four players all have displayed promise either last season or in this preseason and Byner has grown close to all of them, but Ladell Betts, Sultan McCullough, John Simon and Rock Cartwright fully realize they are fighting for their NFL lives.

"That's the most difficult thing in this game," said Byner, who twice made the Pro Bowl as a Redskin and helped lead the team to one Super Bowl title. "The thing I learned as the player development guy in Baltimore was some guys you get to know and develop relationships with and then they're gone. But you also have to understand for the guys that have to move on, there are still guys here. As it is in life there are two sides -- life on one side and death on the other -- and we hope we make the right choices."

Only two preseason games remain to impress the coaches and this Friday's contest in St. Louis is likely most important to Betts, who has missed virtually all of training camp with a hamstring injury. Betts, who will turn 25 this week, was selected 56th overall in 2002. He compiled a 116-yard game in his rookie season, but missed seven games with a broken forearm last season and has been unable to show much to the new coaching staff in practice while missing all three preseason games. Despite a strong pedigree, Betts's health could be a major factor to making the team, as Coach Joe Gibbs is committed to a roster of durable players.

"You've got to have guys you think are durable, because those guys take a pounding," Gibbs said, "and we've been saying it's got to be the kind of people you can count on. At that spot you've got to be a real physical guy to hold up and make it through the year."

Bubba Tyer, the team's director of sports medicine, said there was a 50-50 chance Betts would play Friday, but Byner and Betts said they expect him to participate, likely getting carries early in the game and then rested to prevent aggravating the injury. Betts, who could probably yield a mid to late draft pick in return should he not fit in here, is much heftier than Portis at 222 pounds and could be a short-yardage sledgehammer, but needs to prove his health.

Getting Betts in games "is crucial to the entirety of the team, and it's vital to Ladell to get a feel for what he can do with this offense," Byner said. "I know he can play, but we need to get him out there on the field these next couple of games and I look forward to seeing him."

Betts said: "It's been difficult [sitting out] just from a competitive standpoint, but you have to be realistic. There was nothing I could really do at that point in time. . . . You can't run without a hamstring."

Cartwright, 24, is converting from fullback to tailback -- Gibbs prefers to go with an H-back rather than a fullback, leaving fewer roster spots for running backs -- and won Byner's praises by dropping weight and showing more of an ability to run outside. He was drafted in the sixth round in 2002, led Washington's running backs with four touchdowns last season, and packs a lot of power in his 5-foot-7, 210-pound frame. Cartwright ran seven times for 37 yards Saturday in Miami, including a one-yard touchdown scamper off tackle.

"Rock has come in and done everything we've asked him to do," Byner said.

McCullough, 24, also has experience in this organization, albeit brief. He was signed in 2003 as an undrafted free agent and was inactive for 14 games last season, rushing once for nine yards against Dallas. McCullough (6-0, 197) leads the team with 32 carries and 119 yards in the preseason, playing primarily in the second half against second-team defenses, while breaking one run for 23 yards and scoring one touchdown.

His similarities to Portis may prove a detriment -- both rely heavily on breakaway speed and are not as heavy as most who play this position -- and Byner has asked him to plow up the middle more frequently and use his strength to his advantage.

"He's a very gifted individual," Byner said, "but we wanted him to try and be more of a banger . . . and you could see that sometimes in how he runs up in the hole and gets some extra yards."

Speed remains McCullough's forte, however.

"I know I've got to have an all-round game," McCullough said. "But I know I can hit it downhill and I've got the speed to take it to the end zone. I've got God-given speed and you can't coach speed."

Simon, 25, was signed in November, when Washington's running backs were depleted by injuries, and performed mostly on special teams (he and Betts have returned kickoffs, which could work in their favor as Gibbs makes special teams ability a priority among his reserves). Simon (5-11, 202) played 12 games for Tennessee in 2002 -- winning a roster spot with his versatility -- and he displayed that trait Saturday night, becoming a favorite target of the quarterbacks and catching four passes for 42 yards.

Despite his best efforts, Simon knows the odds could be stacked against him. No one invested a draft pick on him and the competition is stiff. All of the running backs are young and all of them badly want to play, but the numbers simply won't allow that.

"I came in as a free agent, so I know how that works," Simon said. "You really can't worry about competing with the other guys; truly and honestly you can only compete against your best effort. All of us, we all go out -- and we have a great group of backs here -- and give it our best and if that's not good enough and you gave your best, then I can live with that and be happy with that. If my best effort was showcased and I don't make the Washington Redskins team, I can go home to my wife and I can be happy."