The NCAA has reprimanded American University's basketball program for violating preseason practice rules and ordered the school to forfeit a week of practice, prompting officials at AU to question the NCAA's priorities.

While college basketball teams across the country started practicing yesterday, the gymnasium at American University remained dark. The NCAA said Coach Ed Tapscott and his staff "observed and participated in" preseason practices in 1984, which is a violation. Specifically, assistant Chris Knoche played in a pickup game with four AU players, plus five students not on the basketball team.

The NCAA called that an "illegal practice" because Knoche participated. And coaches are not supposed to participate or observe players before Oct. 15.

"Chris did play in a pickup game," Tapscott said. "They considered it an official practice, although I don't know how. The penalty is a little harsh. But I applaud it. We didn't mean to break a rule. But if this is the NCAA's idea of getting tough, I think it's a good thing. I just hope they get tough with everybody."

Tapscott and Bob Frailey, the school's athletic director, wondered why the NCAA chose to expend energy spot-checking preseason practices when major violations are being reported all over the country. The NCAA spot-checked about 50 schools and has reprimanded, either privately or publicly (as in the case of AU), at least 30, sources indicated yesterday.

"The NCAA is confronted with the bubonic plague and it spends time treating head colds," said Frailey, who also sits on the executive board of the NCAA. "You can't watch guys practice? Come on. It's ludicrous . . . This really makes you wonder, when you read about the stuff at TCU and SMU (where athletes have admitted and alleged they were paid by alumni) . . . Somebody's priorities are all mixed up."

The NCAA also said AU violated a rule by "demonstrating stretching exercises, designed to prevent injury, before the legal starting date for practice."

Maryland Coach Lefty Driesell, upon hearing about AU's reprimand, ripped into the NCAA for the second straight day. "That's utterly ridiculous," he said. "Is that a joke? That's what I mean when I called the NCAA a laughingstock. They concern themselves with that when guys keep on getting paid, getting cars . . . If I was AU, I'd just keep on practicing."

At American University, the basketball office is adjacent to the basketball court. Tapscott's door opens onto the court. "If my door is open, I'm 'observing' them," Tapscott said. "They can carry it to any extreme they want."

Knoche, a former AU player, called the reprimand "really frustrating." He said he was sitting in the basketball office when nine students said they needed a 10th man to run a full-court game. "I was just sitting around, so I said, fine. I don't even remember which of our kids were playing. It was just a pickup game. I tell you this, if there's even one of our players on the court now I won't even step anywhere near it."

At other schools, it was a day to begin practice and look toward the season: GEORGETOWN

Coach John Thompson wasn't fretting over the loss of Patrick Ewing. "I'm going to enjoy this season," Thompson said. "I was getting bored the last four years. But I'm excited about this. I see it as a challenge. I'm really up for it."

Thompson has reason to be up. Ewing and Bill Martin graduated, but Thompson said he feels Georgetown has "three players who are as good as anybody in the country at their positions," referring to junior guard/forward Reggie Williams, senior guard David Wingate and senior point guard Michael Jackson.

The Hoyas won't be as dominant in the pivot and power forward spots, but they could be way ahead of most teams with 6-foot-11 senior center Ralph Dalton, 6-11 sophomore Grady Mateen, and Jonathan Edwards, a 6-9 freshman who could spend a lot of time at power forward as successor to Martin.

"We don't have a bunch of invalids out there," Thompson said. "A lot of people are ready to put flowers on our grave. We like that. We love it. We'll go through our growing pains, but we'll be all right. I'm sure of that." MARYLAND

Lefty Driesell pronounced Len Bias "a horse," generally the highest compliment Driesell pays a player. Judging by Maryland's lack of an established center, the 6-8 senior forward, who ran preseason pickup practices harder than Driesell himself, will have to be a real leader.

The Terrapins have a choice at center of 6-8 junior Terry Long, 6-11 junior Bryan Palmer and three freshmen in 6-9 David Gregg, 6-9 Tony Massenburg and 6-11 Phil Nevin. If none of them develops, it will go back to Derrick Lewis, who led the ACC in blocked shots as a 6-7 freshman last year, but whose true position is at forward.

Also, someone has to take the heat off Bias, who averaged 19 points last year and is likely to see double- and triple-teaming defenses all season. When reminded of that, Driesell replied with confidence: "I don't think you can gang up on him too much when the ball is three feet above the rim and he goes up there and gets it."

One more question mark for Maryland is at guard, where there are only Keith Gatlin, Jeff Baxter and freshman John Johnson. So, Gatlin will probably play substantial time as a shooting guard, a prospect that made him smile. NAVY

At Navy, the Midshipmen are starting for the first time with the experience of an NCAA tournament. It won't take until the end of the season for Navy to get noticed this time.

The Sporting News listed the Midshipmen 13th before they officially bounced a ball, and, after the most successful season (26-6) in academy history, Annapolis is abuzz over Coach Paul Evans' crew.

"Ever since the football team (1-4) started having problems, everyone around here is thinking basketball," said junior center David Robinson, a preseason all-America pick based on his 24 points and 12 rebounds per game last year. "The excitement generated (by the NCAAs) was incredible."

Robinson, who considered leaving to attend Georgetown, UCLA or Kentucky after his sophomore year to avoid the five-year military service commitment, put on 10 pounds of muscle to 225 and grew an inch. "He's a little taller," said Evans with a smile. "We weren't going to tell anybody he was 7-foot until after his first class."

The other four starters from last year also return: power forward Vernon Butler, who averaged 18 points and nine rebounds; guard/forward Kylor Whitaker, who averaged 14 points and five assists, plus guards Cliff Rees and Doug Wojcik. GEORGE WASHINGTON

There were two reliable faces missing at Smith Center: graduated center Mike Brown, the leading scorer and rebounder last year, and guard Joe Wassel, the second-leading scorer.

But there was also a new face that provided a comforting feeling for a team that has only two players taller than 6-6. The person was first-year Coach John Kuester, who led North Carolina to the Final Four as a player and coached Boston University to a 31-28 record the last two seasons.

Kuester dominated practice with fast break and defensive drills.

"He's very intense, but at the same time, he doesn't put pressure on you," said senior forward Steve Frick. Said senior guard Troy Webster: "Times in the past, I was nervous on the first day of practice. The attitude is more upbeat." GEORGE MASON

George Mason has a new 10,000-seat gymnasium, Patriot Center, and is trying to build a team that can fill it. Carlos Yates, who scored 2,400 points, could have helped, but has gone and the new faces include Earl Moore and transfer Ken Sanders. Moore, a 6-foot guard, was the Washington area's leading scorer last year, averaging 28.9 points for Cardozo High School.

Sanders, 6-5, transferred from George Mason to Oklahoma and back to Mason, and is ineligible until late December. Sanders averaged 23 points and 14 rebounds in his senior year at McKinley Tech. HOWARD

At Burr Gymnasium, for the first time in 10 years, the Bison didn't practice in the morning. Bison Coach A.B. Williamson, who usually focused on the offense in the morning and defense in the afternoon, wanted the players to concentrate on their classes in the morning.

Howard has all its starters returning, along with center Derek Caracciolo, who broke an arm in the second game last year.

"It feels good to have Derek and the whole team back for a change," said Williamson. "The spirit and hustle was good. There are a lot of jobs that are open and they know that." UDC

Michael Graham didn't arrive until 2 1/2 hours after practice started yesterday and he won't be eligible to play until Dec. 14, but University of District of Columbia Coach Wil Jones is glad to have him.

Graham, a power foward who transferred to UDC last spring after helping Georgetown win the 1984 NCAA title, was late because he had not yet gotten a physical.

"We could be awesome," said Jones. "I can definitely see this team in the Final Four in a year's time. We've just got to keep improving."

UDC, which won the Division II title in 1982 and finished second in 1983, was 11-15 last season.