Running back Gerald Riggs is the first to admit things haven't turned out as planned, the first to admit he has no idea what his future with the Washington Redskins holds.

He has watched Earnest Byner run up the NFL's best rushing numbers the last six weeks, and now that he's about to return from an injury, Riggs knows his role has changed.

When the Redskins bring him off injured reserve to play in Sunday's regular season finale against Buffalo at RFK Stadium, he'll play only if Byner is tired and on some third-down situations. Not much else.

"Heck, Earnest has been the man," Riggs said. "He's been hot, he's doing a good job. At this point, I know Coach {Joe} Gibbs is not going to shake up anything. The offense is going well and the people who are in there now are the people we're going to go with."

Riggs accepts that and knows the remainder of this season isn't about playing time or yardage, but about proving he still can be a productive pro back. He knows people may doubt that. He's 30 years old, has 7,873 career yards and has missed much of the last two seasons with injuries.

The Redskins may even doubt him. They surrendered three high draft choices to get him from Atlanta 18 months ago and have yet to see a significant return on their investment. What they know is that when he has been healthy, he has been as good as any back they've ever had. But the same freak injury that sidelined him for most or all of seven games last season has benched him for six weeks this season.

Most runners never have a sprained arch in their careers. Riggs has sprained his left arch two years in a row, and as he prepares to return to the active roster, he'll be fitted with a custom, steel-shanked orthotic shoe that trainers hope will protect his foot.

He resisted wearing the insert last season and believed the chances of having the same injury again were so remote it wasn't worth the pain and discomfort of adjusting to the orthotic. He knows better now.

Riggs said yesterday the last two years have been "miserable" and the injury has been so painful and slow to heal that he has wondered how much longer he can play.

"I thought when it happened last year it was a fluke," he said, "but it turned out to be more serious than I ever thought. It's strange because I've played with so many other things, but this was something I couldn't shake. When it happened again this year, I thought maybe this was going to be one of those things that'll be the reason I got out of the game. You might have to quit, not because you're beat up but because you had something you couldn't quite shake. The last two years have just been miserable."

The Redskins began this season with an awkward backfield setup. Byner was a No. 1 back in Cleveland, Riggs an NFC rushing champion in Atlanta. Gibbs knew he wouldn't keep both happy, but hoped the Redskins could be successful enough to get them to accept 15 carries a game instead of 30.

That's the way the Redskins played it for eight weeks. Byner had 105 carries, Riggs 100. Byner had 420 yards, Riggs 395.

Both said they were happy. Both fibbed.

"There are situations that come about that a guy just off the bench or a guy coming in from time to time isn't going to pick up," Riggs said. "If you're in there, you get the experience and you get better as the game goes on. It has happened to Earnest and he has probably tapped into some things he might not have known he had. That comes with being in there."

When Riggs got hurt this year, he said he was more shocked than anything. He was coming off an 89-yard game against Detroit, but on his sixth carry against Philadelphia someone fell on the back of his left foot and jammed it into the artificial turf.

He believed he'd suffered a once-in-a-career injury last season and said the days after it happened again, at a time when he'd again been at his best, were awful.

"Believe me, every day you'd get up and question whether it was worth it," he said. "The one good thing is that I knew what it was and what it took to get well. The important thing this time is that they gave me a chance to heal. Last year, every week was, 'Can you play now? Can you come back yet?' It got better at times, but getting back on it too quickly would set you back again. Now I've had a chance to rest it up."

Riggs said watching Byner "kind of reminds me of what I went through at one time in Atlanta. When I got there {in 1982}, there was a guy in front of me {William Andrews} that everybody had spoken of as the best. When he got hurt, people had doubts about how much I could do. I got in there full time in 1984 and had 1,400 yards. It's a game of opportunity, and Earnest has made very well of it. He's had an outstanding year."

But in watching Byner, 28, and the fast development of rookie Brian Mitchell, Riggs said he wonders if he has a future in Washington.

"You can't help but wonder," he said. "But right now I'm just trying to get back. I've had a couple of good weeks in practice, but the true test has to come on the battlefield. It's going to have to be battle tested for me to know what I can and can't do."