For four years, Craig Williams has been eager to play varsity football for the Naval Academy. Today, a combination of persistence and injuries will give the senior defensive back his first starting assignment when Navy plays at South Carolina at 1:30 p.m.

A fullback and linebacker at Roswell (N.M.) High School, Williams spent two years here as a defensive tackle for the lightweight squad, a season on the varsity's kickoff team and the first nine games of this season filling in for injured regulars as safety, cornerback and rover.

Members of the Chet Moeller Fan Club can vouch for the fact that the rover is the key to the Navy defense, the big-play man who eliminates running holes, occasionally blitzes the quarterback and has high-priority pass coverage responsibility between the linebackers and deep secondary.

Until last Saturday, Brian Cianella filled the rover role capably -- causing three fumbles, recovering four and intercepting three passes. Then he suffered a badly bruised foot and Williams took over.

The results were both unexpected and gratifying. Williams was credited with 12 tackles and recovered a Syracuse fumble in the Navy end zone with the Midshipmen leading, 20-10, in a game they eventually won, 20-18.

Williams' work earned him that long-coveted starting role this week and prompted Coach Gary Tranquill to say yesterday, "This may sound funny, but it's fortunate that because of another injury Craig Williams has gotten a lot of playing time recently. We've got guys out there playing who six weeks ago couldn't see the light at the end of the tunnel.

"They've made mistakes, but they've played hard and they've played good football. When the other guys see them come in and do the job, it gives them a big lift."

Williams' performance must serve as an inspiration to scout team members everywhere. His Navy career has been an uphill one since plebe summer, when he sprained an ankle, could not run a 40-yard dash and therefore, as an unrecruited candidate, could not try out for the varsity.

It was suggested that he might want to play lightweight football. There was just one catch. Williams weighed 178 pounds and the lightweight limit, which had to be certified each Wednesday during the season, was 158.

"The reason I did decide to play with the 150s was that football was my favorite sport and I really wanted to play," Williams said. "But losing the weight was terrible. From Monday to Wednesday every week, I would not eat or drink anything until after the weigh-in. I'd be drowsy in classes and it was tough going through practice without much energy. Then, Wednesday evening we'd pig out and the weight would be back up by Friday or Saturday."

After two seasons of starving off 20 pounds from Monday to Wednesday, Williams received permission to join the varsity for spring practice.

"Paul Soares was in my company and he suggested I talk to Coach (George) Welsh," Williams said. "It was winter of my sophomore year and he said they had too many guys weightlifting, so I had to do it on my own. Then I ran the 40 in spring break and even though it was only 4.85, he let me come out.

"I had played defensive tackle with the 150s because I was one of the bigger players and it was a very big change to defensive back. Different techniques and different skills were required. I made about half the trips my junior year, but except for going in occasionally on a kickoff, I stayed on the bench. It was very frustrating."

Things got no better during practice last spring. Williams was involved in an automobile accident and required stitches in his head. He missed most of the drills, a particularly inopportune circumstance with the new coaching staff coming in.

Nevertheless, Williams lifted and ran most of the summer, even jogging around the deck of a destroyer on a cruise from Charleston, S.C., to Rota, Spain. By the start of summer practice, his 40 speed was at 4.7 and his weight was up to 188.

Over the first six games, Williams saw limited duty, until numerous injuries sent opportunity and Tranquill knocking at his door. Williams has played the last three quarters of each of the last three games.

Elsewhere today, Howard University goes after its fifth straight victory when it plays host to Western Illinois at 1 and Virginia (2-6) travels to North Carolina (5-3) for a 1 p.m. game.

There are several critical games around the nation, with the major bowls watching closely.

If Arizona State (9-0) can defeat Washington (8-1) in Tempe tonight, the Sun Devils will clinch the school's first Rose Bowl bid. For the Huskies to go to Pasadena for the third straight year, they must beat Arizona State today and Washington State (2-6-1) next week. The Cotton Bowl also will have a scout in the stadium.

Representatives from all the major bowls will be in South Bend today to watch the Irish ((6-1-1) play host to Penn State. The winner should get a major bid, and the loser most likely will get an invitation to the Fiesta Bowl. The two perennial football powers have never played before, and a national television audience (WJLA-TV-7) will witness the first meeting.

Georgia, fresh off its 44-0 victory over Florida and a move into the No. 1 position in both wire service polls, travels to Auburn. A Georgia victory will give the school its third straight Southeastern Conference championship. Herschel Walker has rushed for 219 yards two weeks in a row and could make it three today.