Patrick Ewing walked onto the floor at McDonough Gym at 4:10 p.m. yesterday, the way cleared for him by Bill Stein, an assistant coach.

There were several reporters and a camera crew in the gym but no one made a move toward Ewing. Everyone knew Coach John Thompson's edict: no one talks to Georgetown's most prized acquisition since the C&O Canal was completed.

Ewing, wearing No. 55 on his practice jersey, his knees wrapped in white pads, picked up a basketball and joined senior Ron Blaylock, who was casually shooting at a basket.

Holding the ball like a baseball, Ewing walked to about eight feet from the hoop and took a soft, flat-footed shot. It went through the net and the 7-foot freshman smiled. He was one for one at Georgetown.

All over the area yesterday, beginning at 6 a.m. at Howard and ending at 9 p.m. at Maryland, college basketball teams were taking their first practices for the 1981-82 season.

At Georgetown, while five freshmen loosened up unburdened by questions, the veterans patiently talked about what they expect the next few weeks.

At American, Coach Gary Williams was delighted to see his players show the same kind of intensity that produced last season's 24-6 record. At George Washington, Gerry Gimelstob started his first season by talking about defense, conditioning and fundamentals. He told Mike Neville, 20 pounds overweight, that he wouldn't practice until he loses the weight.

At Maryland, Lefty Driesell welcomed the least-heralded group of players he has had there since the pre-Tom McMillen-Len Elmore era.

Driesell drilled his 12 players remedially. The Terrapins, minus four of last year's starters, will work solely on defense the first two weeks.

"Sometimes it's more fun to coach a group like this," Driesell said after putting his team through a two-hour workout in Cole Field House. "It might not be much fun when the game starts, but it's fun in practice. Last year with all those seniors, we were running five-on-five drills the first day. Today, we didn't get past one on one."

Driesell was pleased with the condition of his players. But center Taylor Baldwin had problems with his right knee and couldn't go full speed in some drills.

At Howard, Coach A.B. Williamson got his first scare of the season when it appeared that a knee injury might sideline 6-8 freshman Kevin Thomas. But yesterday, Thomas practiced.

At UDC, Earl Jones started his second year with Coach Wil Jones hoping this ride will be smoother than last year's. At Virginia, Terry Holland talked of a quicker team. Ralph Sampson, who is living in Holland's basement this year, said, "the more the merrier," when the question of double- and triple-teaming was raised.

At George Mason, Coach Joe Harrington began his second season full of hope, mostly because of the return of Andre Gaddy and Terry Henderson, both of whom sat out last season injured.

Nowhere was the anticipation greater than at Georgetown. And nowhere was the tension more apparent. "You want the pressure though," said Eric (Sleepy) Floyd, now a senior and this team's leader. "That's what this game is about. If you don't have expectations, what's the point?

"I would expect the practices will be very competitive. I already know the freshmen aren't going to back down to the older guys from playing with them. I read a lot of stuff about these guys and they haven't let me down at all so far."

Perhaps Floyd's last comment explains the tension. How many college programs are faced with a situation where the leading scorer has been reading about the freshman, rather than vice versa?

But that is the way it is with Ewing, William Martin and Anthony Jones on hand. Ewing was last year's all-everything recruit and Martin and Jones were rated in the top 10 among high school seniors.

What they think about their new environment will remain a mystery to the outside world until Jan. 1 because Thompson has strict rules about who can and can't talk to his freshman. He can. The media can't.

"That's the way we've always done it, only in the past no one noticed because no one wanted to talk to the freshmen," Thompson said. "I'm not going to change the program now. The kids came here to be part of this program the way it is."

Not changing also means that anyone who wants to get a sneak preview of Ewing in practice will do so at his own risk. Thompson's teams always have practiced privately and he says he won't change that rule either.

It appeared yesterday that the no-interview rule was one Ewing will live with quite happily. As he warmed up, he joked loosely with teammates, oblivious to the intruders in the gym because he knew they would not be bothering him.

"All Patrick has to do is keep a level head and he's going to be fine," said senior Ed Spriggs, who will likely back Ewing up at center once the season starts. "As long as he doesn't get too up or too down, he should be ready for all that's to come."

All That's To Come may be the theme in McDonough for the next six weeks because a lot is expected of this team and of Thompson.

A moment later, Thompson blew his whistle and walked to center court. As his players formed a circle around him, Thompson put his hand out and each player reached in to get his hand into the circle.

The gym door swung shut. It was time to begin.

Some coach's comments from Day One:

Gary Williams, AU: "It felt strange being back out there. I wondered how the kids would react, but it was great. They were aggressive and worked hard. Last year we were winning and knew we were going to play well so it was easy to practice hard. Now, we're 0-0 and they practiced hard. I felt real good about it."

Gerry Gimelstob, George Washington: "We're going to work hard putting in the new system. I've got to get to know these kids and they have to get to know me. It's going to be a very interesting six weeks. I'm excited to get started."

A.B. Williamson, Howard: "We'll be working on offense in the morning and defense in the evening. I'm hoping Thomas will be okay. He's going to be doing stretching exercises to make sure the knee doesn't lock on him."

Joe Harrington, George Mason: "We're just working on fundamentals right now. I feel a lot more relaxed, a lot better organized than my first year. We're a lot stronger and we've got a lot more depth this year than last. That's got to help. Nobody got hurt today; that's a good start."