National Football League Commissioner Pete Rozelle announced yesterday at the NFL meetings that there will be a "dry-run" study done on the use of instant television replays during seven nationally televised exhibition games in 1978.

But Rozelle said there will be no implementation of the system during the regular season.

The results of the study by an observer in a separate booth will not be made public game by game. Game officials will not be overruled by the observer. There will be no communications with the officials on the field.

Rozelle said the owners may discuss results of the study at their usual midseason regular meeting, but said a full report will not be made until the spring, 1979 meeting in Hawaii.

The decision yesterday was by a unanimous vote but there were some negative sentiments by owners, suggesting that it is unlikely that instant replays would be considered even for the 1979 season.

The reasoning is that instant replays may create more problems than they solve. It was said that the owners want to go very slow.

One of the problems is that the use of immediately available electronic evidence is that it might show several fouls on a play while it tries to clear up the question of, say, a controversial fumble.

Another problem is the possibility of not being able to come to a conclusion after holding up a game.

Rozelle cautioned interviewers, "I don't want to unduly optimistic that instant-replay use is near. Nor do I want to seem pessimistic.It is just an openminded study."

Asked if the study was at least an exercise in public relations, the commissioner said, "It's to demonstrate that we're openminded. Obviously, that's public relations."

There was a groundswell, measurable in media reaction, of public demand for a trial of television replays to prevent repetition of highly critized calls last season on dropped balls by Bert Jones of the Baltimore Colts and Rob Lytle of the Denver Broncos that were not ruled as fumbles.

The NFL made a one-game study of the use of instant replays in 1976, when Buffalo played at Dallas in the regular season. The network television cameras were augmented by equipment employed by the league.

An estimate was made at the time that such a process would cost $200,000 a game or $50 million a season, with 14 crews needed. Rozelle said yesterday one of the problems would be in trying to find competent personnel.

He pointed out that the films on that game were not clear on several important plays.

The plan now is to study the feasibility of depending on the network telecast only. The NFL observer in the booth might ask to be shown shots taken but unused by the network, to check against the picture shown to viewers.

Later in the week, the observer would also look at game films. He would have a stopwatch to determine how long it would take to call back action and study it for a decision.

He would chart all the plays to determine how many involved questionable calls by the officials.

The first exhibition on a network telecast will be a game between the Miami Dolphins and Philadelphia Eagles July 29 at Canton, Ohio, in connection with National Professional Hall of Fame enshrinement ceremonies.

One owner, Bill Bidwill of the St. Louis Cardinals, said of instant replays, "I am not in favor of taking the game from the field and putting it in a television booth."

Jim Finks, general manager of the Chicago Bears, said, "We have to try the instant replay, but nobody thinks it's going to be the answer. Maybe we're wrong."

Steve Rosenbloom of the Los Angeles Rams said, "It's not feasible at this point. Technologically, we might be able to make it work (with the use of costly equipment to back up the network telecast) if we had enough money. The fans have asked us to try instant replay and we will see if it will work."

The owners also moved back the deadline for trading between conferences from after the final cutdown date in the exhibition season to be Tuesday after the sixth regular-season game, to coincide with the deadline on trading players within conferences.