Less than 24 hours after the United States Football League had achieved instant credibility by signing a $20 million television contract with the ABC television network this week, Berl Bernhard already had received three serious inquiries about purchasing part of his Washington franchise.

"This place is a madhouse," Bernhard said about his law offices-turned team-headquarters. "People have been calling all day . . . Suddenly, everyone realizes we are very serious about what we are doing. This is no joke."

Still, there are questions about the league, particularly involving players. Where will they come from, and can the USFL sign enough quality players, considering the competition from the National Football League, to justify the new television contract and the financial commitment of its investors?

ABC made its decision based on the credibility of the owners, who hardly are lacking for resources, and on the disciplined organization of the league, which waited a year to start when some parties were pushing for a March 1982 kickoff.

ABC admittedly was searching for legitimate sports programming in the spring, a traditionally weak period for network sports departments. Still, ABC is taking a remarkable gamble, considering the USFL has yet to sign a coach, a player or a stadium lease.

No one--not USFL founder David Dixon, not the owners, not ABC--knows for sure what kind of product the network will be showing in March. Will it be another version of the World Football League, which died when it could not get national television exposure? Will it be one step above minor-league football, but one or two very major steps below the NFL? Or will it be as exciting and as unpredictable as the American Football League in its infancy?

"We'd look very, very silly if we don't produce a first-rate league the first year," said Peter Spivak, the USFL's acting chairman until a commissioner is hired, probably within a month. "I think there are enough players out there who will make us awfully good. We aren't going to waste our time with the NFL retreads. My goodness, these men don't have to invest in this league. They have better things to do with their money, I'm sure. So they aren't going to be embarrassed by producing a bad product."

Added Bernhard: "I think our first year is crucial. If we expect the support of fans, we can't put out a bad product out of the blocks. People will be surprised by the quality we will have. If I didn't believe that, I wouldn't be here. I feel very, very strongly about it."

Spivak envisions a first-year league comprised of "many young, quick, exciting players." Bernhard envisions an attractive league featuring top-name players who will finish their college eligibility this fall. Some in the league believe that disenchanted NFL players, especially those who will be free agents next winter, will flock to the USFL if the money is right.

The Associated Press quoted Randy Vataha, one of the co-owners of the Boston team, as saying there have been informal discussions about the possibility of pooling resources from around the league to lure Georgia running back Herschel Walker out of college and into the league.

The league will need at least 500 players to fill out the 12 rosters. Squad limits have not been set, but will probably range from 40 to 45 players per club. To prevent an internal bidding war, there will be a ceiling, the same for each team, on total player salaries.

As Dixon said last August, "Every now and then, some of us seem to forget just how effectively we can compete with the National Football League in signing player talent without huge budgets."

To find enough players, the USFL at first will be forced to take athletes who either have been recently cut by NFL teams or have had some NFL experience.

Bobby Beathard, the Redskins' general manager, admits that many of these athletes "have talent. Lots of time, there just isn't room on the roster for them. And some are guys who, in two or three years, develop into really decent players. I think they also will have a lot of players who come back here after playing in Canada or who would play in Canada if the USFL didn't exist. I just can't see the quality level being that high."

But Spivak and other USFL officials feel they also can compete successfully with the NFL for college seniors entering the draft pool. They cite the league's unique draft system as one reason.

"We will have a territorial setup where certain colleges will be assigned to each league team," Bernhard said. "So, for example, players at Maryland or Virginia would belong to my team. For teams like New York, which don't have good local college teams, schools from other areas will assigned to them, like an Oklahoma to New York, for example. Then, all the players from colleges which haven't been assigned a specific league team will be placed in a pool and subjected to a draft by all the teams."

Says Spivak: "We can say to a guy from USC: 'You can come into our league, be an instant starter in a big-league town where you went to school and everyone knows you. You will get national television exposure right away, you'll have media attention, you'll be playing against teams from other major cities. You will be getting in on the ground floor of something that will be very, very big.' "

The league also believes it will benefit from a December draft, four months ahead of the NFL selection process.

"Our draft will result in a change for the better for football," Spivak said. "The player agent will have to become more of an adviser. The athlete will be drafted by us in December. He now will have a decision to make. Should he sign with us and be playing in March or should he wait until April for the NFL? Even the good ones who know they will be drafted will have to wonder whether sitting on the bench in that league or starting for us is better."

The USFL intends to sweeten the lure by offering guaranteed contracts (rare items in the NFL, expecially for rookies) and immediate salary payments, plus, possibly, scholarships to help finish off college degrees, and family job counseling.

Dixon long has preached that the league should concentrate on signing players who normally would be drafted by the NFL in the fifth to 12th rounds. He argues that guaranteed contracts and decent salaries would sway prospects toward the USFL.

Dixon also says that a salary budget of $2 million per team could allow USFL teams to go after big-name college players. If clubs sign 30 players at $20,000 to $35,000 each, that would leave a substantial pool from which 12 more talented athletes could be signed, at salaries ranging from perhaps $300,000 for a first-round choice to $40,000 for an eighth-rounder. Considering NFL first-year players last year averaged $55,000, Dixon's projections may not be far-fetched.

"We are not going to get into a bidding war, especially for players already in the NFL," Spivak said. "We are the second season, not a competing season. Otherwise, we could have had a draft already. We don't want to go that route."

There is no question that the ABC contract has heightened interest in the USFL and given the league a major boost. Bernhard already has received applications from 19 coaching candidates, including five he considers "serious prospects."

By Friday, 19 athletes had asked for tryouts "and even more people than that want to be cheerleaders," he said. "It's gotten so bad that we've got two or three people tied up taking calls and screening things."

And this for a team that doesn't have a nickname or a lease for RFK Stadium, although Bernhard feels he is close to an agreement with the D.C. Armory Board.

"By July 1, I anticipate that we will have a commissioner and all our head coaches hired," Spivak said. "It may take longer than that to wrap up the stadium leases. But I can tell you this: I have already received enough inquiries from investors to launch 12 more teams if we wanted to. But we don't."

The USFL's next announcements will deal with coaches. The owners have agreed to spend big money (private estimates range up to $250,000 a year) on salaries for the head coaches, who preferably will be visible, well-regarded football men. League thinking is that the coaches will provide further instant credibility while player skills develop.

"The key for us has been that we've concentrated on taking care of the financial aspects of the league first," Bernhard said. "We now have the substance to survive and endure. Now it's time to get on with the rest of our business. Things are going to really take off, I'm sure of that."