After threats of a player strike for more than a year, the MLB Players Association took its members out on a strike that began June 12, 1981.
A book called “Split Season 1981” by Jeff Katz — well worth reading, incidentally — described what happened in great detail. Here’s what Katz said about it in a radio interview in 2015:
... the owners started throwing money around in ways that was quite shocking to themselves, as well as the players. And realizing they couldn’t control themselves, tried to collectively bargain a way into controlling themselves, which was in effect to make free agency into a trade.