Thursday, National Hockey League executives will sit close to their telephones as they serve up the most promising influx of young talent to reach the league in 20 years.

What was formerly tabbed the amateur draft has been christened the entry draft, because some of the eligible players performed as pros last year in the World Hockey Association.

Additionally, all youngsters who reach their 19th or 20th birthday in 1979 may be selected, rather than just the usual 20-year-old crop.

Colorado will pick first, followed by St. Louis, Detroit and Washington. Normally, these teams would now be hounded by the better clubs, who would have little chance of obtaining a quality player because of their late selections. However, the depth of talent promises to give even the Edmonton Oilers, choosing 21st and last, solid help.

Ray Miron, general manager of the Rockies, who had the NHL's poorest record a year ago, was entertaining bids for the No. 1 selection, but found an almost total lack of interest.

"With the 19-year-olds in the draft now, there are more good players available," Miron said. "Before, when you could pick only 20-year-olds, the teams picking, say, 10th, 12 or 14th weren't going to get much of a hockey player. Now they're going to get a pretty good hockey player, so they're not interested in giving up all that much to get our pick."

Miron said he probably would choose Rob Ramage, a defenseman who was a WHA all-star with Birmingham last season. But he also indicated interest in Perry Turnbull, a left wing for Portland of the Western Junior League.

"We're leaning toward Ramage I guess, but there's nothing definite yet," Miron said. "We're not going to commit ourselves to who we're going to pick until the last minute."

In past seasons, because of WHA competition, the team picking first would sign its No. 1 selection before the draft, to insufe that it did not wasts such a vital choice. Then, it would reveal its man to the next club in line, so it could do the same.

Because of this, the Capitals signed No. 1 pick Rick Green before the 1976 draft and had Roberst Picard signed before choosing him in 1977, even though he was the third man overall. Last season Ryan Walter was verbally committed before the Capitals made him the second selection in the draft.

This time uncertainty of others' intentions make it difficult even to speculateon the Capitals' likely first selection Thursday.

"Ray's argument is that there is no other league to go to, so there is no reason to solidify things early," said Washington General Manager Max McNab, who prefers to have a tighter control of developments. "It starts out with Ray, so we will just have to wait."

Compounding McNab's problem is the necessity of a fast start by the Capitals to sell tickets. They desperately need a forward who can help right now, like Cincinnati's Mike Gartner or Birmingham's Ricky Vaive, the WHA penalty king, and therefore cannot gamble on an underage junior with superstar potential, like Oshawa winger Tom McCarthy, a 144-point scorer, or Verdun defenseman Raymond Bourque.

Once beyond that key first choice, however, McNab may deal in futures, with a particular eye on Minnesota defenseman Mike Ramsey, a U.S. Olympic selection.

"There was a very basic mistake made here the first few years, particularly regarding college players," McNab said. "Even in the fourth or fifth round, there was priority given to the need for somebody to play now. A guy picked in the fourth or fifth round will be in the minors anyway. It's worth waithing a year or two for a superior talent."

The better teams, of course, can afford to wait even for a first-rounder to develop. So McCarthy and Bourque are likely to go to strong teams that eventually will get stronger. That is the way the underage draft hurts the weaker teams like the Capitals. A McCarthy or a Bourque will not be around next year to become a first or second pick.

Player agents in search of fat commissions have been plugging for the WHA proso to be exempt for the draft, instead selling themselves as free agents to the highest bidders. Barring last-minute legal action, however, they will be included.