The returning National Football League players weren't ready to hug the replacement players or those veterans who had crossed picket lines during the 24-day players' strike. But there were no major incidents reported yesterday when all the players, union members or not, mingled for the first time in locker rooms and on practice fields throughout the league.

Meanwhile, several club executives acknowledged the possibility that a split season and/or additional playoff teams could be discussed next week in Kansas City when the league owners hold their annual fall meetings.

Joe Browne, an NFL spokesman, said yesterday that there "are no plans in this office at this point to do anything different with the season. We can't predict what a particular club will do or say at the meetings. But it is not on the agenda and we don't expect anything."

The clubs that would be in favor of increased playoff participation, at least theoretically, would be those teams that were expected to make the playoffs, but suffered two or three losses in replacement games. That would include the Super Bowl champion New York Giants (0-5), Minnesota Vikings (2-3 after a 2-0 start) and the Los Angeles Rams (1-4).

"We would be in favor of an expanded playoff system, and I think it is something that needs to be discussed on the league level, the pros and cons of doing it," Mike Lynn, vice president and general manager of the Vikings, said yesterday.

Lynn said he thinks it "is important" that the replacement games count because the league has promised as much, but added: "If there are ways in which the integrity of our playoff system could be maintained, either by an expanded or split season, we would be in favor of it.

"When 26 of the 30 teams in the last three years get in by a margin of two or less games, and we played three replacement games, it is important that we maintain the integrity of the system."

George Young, vice president-general manager of the Giants, said his club will not make such a proposal even though a revamped playoff system of any kind would help the Giants more than any team in the league. "I've heard people saying things," he said, "and, if somebody else wants to propose it, then fine. But I can't. We dug a hole for ourselves {the veteran Giants were 0-2 before the strike} and we have to dig ourselves out. We shouldn't be looking for sympathy.

"If the league decides to make some adjustment that the owners feel is in the best interest of the league, that's one thing. But we wouldn't want to be one of the teams making the proposal."

In 1982, because of a 57-day players' strike, the league decided to allow eight teams in each conference to make the playoffs, instead of five each. But the league played only a nine-game regular season schedule that year.

A more immediate concern for most teams, including the Giants, is getting the regular players and any remaining replacement players ready for this weekend's games.

"The teams that put all this silliness aside and start thinking about football again will be the most successful teams the rest of the season," said Dallas Cowboys President Tex Schramm, who has been opposed to changing the season schedule or the playoff format.

But not all of his Cowboys were ready to put aside hard feelings. Doug Cosbie, the team's union representative, didn't hide the fact that he didn't want 20 replacement Cowboys in the dressing room at Valley Ranch. "They shouldn't be here," he said. "We don't need a lot of extra people around."

In Minnesota, defensive lineman Stafford Mays is the only replacement player who will play with the regulars. "Everyone said, 'Hello, scab.' I knew I was going to take a little ribbing, but it was good-natured," he said.

In Chicago, the Bears voted, 44-1, to prevent the replacements from joining the regulars, but Mike Ditka said he "vetoed" that and doesn't care what the veterans think.

The Bears did get some news that Ditka and the veteran players were glad to hear when quarterback Jim McMahon announced he is ready to play this week at Tampa Bay, "and if I do well in Tampa Bay, I'll expect to start the following week."

The Bears have won 23 straight games that McMahon has started, but Mike Tomczak has won eight straight and this could be the start of a quarterback controversy.

"I don't think I did anything before I got hurt to lose my starting job," McMahon said. "Tomczak has played well . . . But I can do things on the field that he hasn't gotten to yet."

Tomczak replied: "I've been pulling for him. But the better quarterback is going to play, and right now I'm playing well . . . "

The Houston Oilers could benefit from the services from first-round draft pick holdout Alonzo High- smith. But his status -- as an Oiler or a free agent -- won't be determined at least until Friday when a hearing is scheduled in Miami.