Ordinarily, with proper care, an 18-wheeler can be expected to chug along for at least a million miles; the Redskins' diesel, John Riggins, is talking about needing some rest -- and he hasn't even logged his seventh NFL mile yet.

But these trucks don't travel the same highways; the Riggins Route usually is more confined than a back-country cow path. Tackle to tackle is more narrow than most one-way streets, minus potholes.

Ah, but the million-mile diesel is not asked to bang through something equally massive coming equally fast the opposite way. Or to run over smaller trucks and cars, even though it seems that way on many interstates.

Nobody has earned a rest more than Riggins. Few, if any, backs ever have run more often over so long a time, or into more obvious ambush. Most plays, Joe Jacoby and Russ Grimm could whisper to the nasties nearest them: "Psssst. We're comin' your way."

And still gain five yards.

Possibly, Sandy Koufax could have told hitters what he would throw every other pitch and still made the Hall of Fame. Wilt Chamberlain rarely shot more than a few feet from the basket -- and still averaged 30 points a game for his career.

But the ball seldom nailed Koufax; there were fouls to protect Chamberlain when the maiming became too obvious. Lotta harm, still no foul in the game Riggins plays.

At 35 years, three months and two days, Riggins said he must rest sometime this season, and hinted strongly that this just might be the week.

During the only press conference ever when the subject was seated atop a drinking fountain, Riggins said, "There's a very good chance I won't play Sunday (against the Detroit Lions in RFK Stadium). This has gone a bit too far."

Last night, he backed off a bit, saying in an interview on Channel 7 that "as long as I'm able to play, they're never going to be able to overwork me. I've got the machine that can handle all the overloads . . . The question is if this machine can play from Sunday to Sunday? And it has been a question from Sunday to Sunday."

Riggins has been averaging 25 carries a game for the last three years. Even the most durable diesels need to get the batteries recharged once in a while.

After 32 fist-in-the-face carries for 100 yards against the Falcons Monday night, Riggins wearily volunteered, "Tonight really felt like a beating."

Franco Harris, the back with the most career carries in the history of the NFL, only averaged 17 over 173 games.

Walter Payton has averaged 21 carries a game; the best back football has known, Jim Brown, scarcely averaged 20; even the Redskin everybody said George Allen ran into the ground, Larry Brown, averaged just 15.

Riggins is larger than each of them, and may well have better blocking; he also is older, a 35-year-old punch the Redskins telegraph nearly the entire game.

Let's leap into the mind of a middle linebacker as he contemplates Riggins. Surely he is saying to himself, "He ain't fast enough to go outside; he's the only guy back there; he's got two all-pros on the left; think I'll move me half a ton of tacklers that way."

Riggins averaging five more carries a game than the immortal Brown might not seem all that much. Except it would mean having Sam Huff wrapped around his throat 60 more times a season. Or someone almost as mean. Besides, Brown retired after his ninth season; this is Riggins' 13th.

Every Redskin also takes his lumps off the field, and Riggins has been called "poor little rich kid" by special teams pixie Pete Cronan.

"I tell him once he signed that big contract (that ends after this season) he's takin' it easy," Cronan joked after the two-touchdown victory over Atlanta. Like the other Redskins in the dressing room, active and inactive, wounded and healthy, Cronan knows Riggins has earned every penny.

"This is a team of role players," Cronan added. "Players who do specific things very well. But that role business also goes a step farther, to knowing what's expected of you.

"John's expected to rip off those 100-yard games; to get the first down when it's needed."

Riggins said Monday night a decision on whether he plays probably will be made before game time Sunday. Publicly, he has been talking about a break for more than a month.

"It'd be good for him," quarterback Joe Theismann said.

"He's been suckin' it up for five or six weeks now," said Grimm. "It might be bothering him a little on the field, but where you see it is two days or so after the games.

"He's so stiff his hips hardly even move. You don't like to see that happen to anybody. If we could have given him a rest, we would have."

Exactly. The problem with running Riggins so often in the regular season is that it would create a situation in the playoffs where he might simply sputter and stop. Crankshaft, spark plugs and pistons scattered about the field.

"But we've gotta use him," said Grimm, grimly, "to make sure there's a playoff situation."

A finesse seems imminent, the Redskins hoping they can spell Riggins for a week and still win. The Lions would be the proper time, the game being during a short week and against an ordinary team with its Billy Sims also out.

"I didn't pick my holes well or run well," Riggins said of the Falcons ordeal. "My eyes gave out on me. Usually, they're 20-20 (at finding holes).

"That's kind of surprising, since the (stiffness) fog seemed to have lifted late in the week. I felt as good as I had before the New Orleans game in the exhibition season. I felt tonight that maybe it would go the other way."

Painfully, it did not.

Could he describe the late-week misery that makes his body seem mummified?

"No," Riggins said, "but an 85-year-old man could."