World Team Tennis (WTT) has adopted a plan, novel for a professional sports league, whereby all players after May 1 of this year will be signed to contracts by the league and then assigned to individual teams by draft.

The new system, designed to keep player payrolls at a realistic proportion of each team's operating budget and to avoid legal problems that have struck down the traditional draft systems in other sports, was given preliminary approval in January. It was "reapproved" at a meeting of the WTT board of directors in New York last week, according to Larry King, president of the New York Apples and director of properties for the 10-team league.

"We are still refining the plan, working out the exact numbers, but we are definitely going ahead. The board appointed a committee to implement it for a 1978 season," said King, one of the founders of WTT and its immediate past president. He is the husband of Billie Jean King, who plays for the defending champion Apples.

Since its inception in 1974, WTT has operated in essential the same manner as leagues in other pro sports. Individual franchises have signed players, often bidding up the price of talent to the extent that teams could not make a profit because of their high payrolls.

Under the new systems, King said, the league will project its revenue from all sources - ticket sales, television, properties, etc. - and then determine how much it can afford to spend in player salaries. It will then sign the most attractive group of players it can whithin that budget allowance.

Players signed between now and May 1 will have contracts with Individual teams, and existing long-term contracts will be honored. But all players signed thereafter will have league contracts, King said.

All players signed to play WTT in 1978 will be distributed to teams in a six-round draft in November. Teams will choose players in the reverse order of their finish in the 1977 league standings, King said.

Teams will have the option of keeping any players on their 1977 rosters, King said. For each player it protects, a team will give up its selection in the appropriate round of the draft. Trading of players between teams will still be permitted.

The plan has legal as well as fiscal dimensions.

"Every draft that has ever been made has been declared illegal because the rights to a player were distributed without the player's acquiesence," said King, whose law school concentration was in anti-trust law. "In this draft, only players who have allowed themselves to be drafted will be."

Each WTT team will have a roster of three men three women. There are currently 10 teams in the league: Boston, New York, Pennsylvania (which will operate a team of Soviet players in 1977), Indiana, and Cleveland-Pittsburgh in the East Division; Los Angeles, Dan Diego, Phoenix, Golden Gate and Seattle-Portland in the West.

WTT teams currently play a 44-match schedule running from late April through late August, but both the length of the schedule and the dates could be changed for 1978.Some WTT teams are playing outdoor matches for the first time in 1977, and there has been some discussion of pushing the WTT season back so that it begins after Wimbledon and finishes in the fall.

Meanwhile, it has been learned that Ilie Nastase would like to play the second half of the 1977 season for the Los Angeles Strings. The Strings are considering signing Nastase to a three-year contract worth more than $1 million.