There is no joy in Mudville, mighty Casey has gone out on strike. For the first time in the history of professional sports, athletes have gone out on strike in the middle of the season.

Marvin Miller, the executive director of the Major League Baseball Players Association, looking tired and dejected, said early this morning, "We have been meeting most of the day. We have accomplished nothing. The strike is on."

Miller ordered all teams to return home.

Miller said that the owners had requested a meeting for 10:15 this morning and that the players association would be represented, but not by him. Earlier in the week, Miller had said that if there was a strike he would not participate in the talks.

Making the announcement at 12:45 a.m., Miller said, "We asked if they expected to have any new ideas, if they did, we would stay another two or three hours tonight. They said no. We asked why they wanted to meet tomorrow (Friday) and they said they wanted to."

The players association went on strike in 1972 for 13 days over their pension plan and they struck the last eight games of the 1980 spring training over the free-agent compensation issue, which has prompted this strike. A source close to the players association predicted that this one would be much longer, "perhaps all season."

Currently teams that lose players through free agency are compensated by a pick in the amateur draft. Under the owners' original plan, in many cases compensation would be the 16th player on a 25-man major league roster.

Wednesday, a federal judge in New York ruled rejected a National Labor Relations Board request for an injunction that would have delayed implementation of the owners' compensation plan until next spring. At that time, the players announced that if no agreement was reached by this afternoon's first game -- the Cubs versus the Padres in Chicago -- they would strike.

It is characteristic of these negotiations that in the end, the parties could not even agree that the strike had actually begun. Ray Grebey, the chief negotiator for the owners, following Miller to the podium, said, "The strike is a near certainty. Though there is a bargaining session scheduled for tomorrow, the strike officially begins at 2 p.m. . . We don't take bargaining sessions lightly."

"You mean there is a ray of hope," he was asked.

"I see very little hope," he replied. "If they call a strike before the bargaining session, it tells you what they expect to happen at the session."

Don Fehr, the general counsel of the players association, shook his head, as Grebey's remarks were relayed to him. "Ray says the game's not scheduled 'til tomorrow afternoon. I just got off the phone with Reggie Jackson. The Yankees are going all kinds of places and none of them is Minneapolis to play the Twins."

There was no doubt in the mind of federal mediator Kenneth E. Moffett that the strike was on and by 8 p.m. Thursday, he knew there would be one. "The parties are 10 miles apart," he said.

Free-agent compensation, the only strike issue, proved to be as intractable during 11th-hour negotiations Thursday, as it has been for the last two years. During the morning and afternoon bargaining sessions, the owners made a new proposal, which the players association described as "insignificant."

The owners proposed changing their free-agent compensation formula to include only 40 percent of all players instead of 50 percent, according to Fehr. Also, they offered to make the reentry draft no longer secret but stipulated that no team could pass a round without being eliminated from the draft. But, Fehr said, the owners' proposal still meant that the team signing a free would have to give up its 16th player for the top 33 percent of players, and the 19th player for the 34-40th percent of players.

Fehr said, "A year ago, they knew that along with everything the players got, if this was on the table, they had a strike. Essentially, the proposal is the same as a year ago so they never had any reason to believe that they would get a response other than a strike, which leads you to believe that was their design from the beginning."

"This issue can only be solved at the bargaining table, and we have two years invested in this," Grebey said. "We will be here to continue negotiating even if there is a strike.

"A strike is not a pleasant experience to anyone but, unfortunately, the differences are very significant and the obstacles were too much to surmount."

When the negotiations resumed after dinner Thursday, at 8:30 p.m., the players association offered a variation on the proposal for pooled compensation that they made last week. Instead of each club putting the 40th man from its major league roster into a pool, the players suggested that each club would designate four players on the 40-man roster for the pool that a club losing a free agent could select from. But a club that does not select a player in the reentry draft would not have to put any players into the pool.

Grebey reiterated that there is no way the owners will agree to a plan that allows for a team to sign a free agent without having to directly provide compensation.

In its news proposal, the players association also increased the amount of money the club selecting a player from the pool would have to pay. If the club selecting the player from the pool is in the top half of the league, it would pay $60,000, a 50 percent increase over last week's proposal. If the club that selected the player was in the bottom half of the league, it would have to pay $30,000. And if the pool player is selected from a club that signs a free agent, then there would be no financial cost.

"They termed it a worse compensation arrangement than they had after the (Andy) Messersmith decision," Fehr said. "Which is strange because it gives them far more compensation than previously existed."