Spanish football will be suspended from 16 May because of a dispute over TV rights.
The Spanish football federation and the government are at odds over the way TV money is distributed.
The suspension - which will affect more than 600,000 players and 30,000 matches - comes as Barcelona lead La Liga rivals Real Madrid by two points, with only three games left to play.
The Spanish government has approved a new law on collective bargaining for TV rights, although this has yet to be passed.
The National Professional Football League (LFP) - the body responsible for Spain's top two leagues - supports the law and has begun legal action to try and block the suspension.
Currently, Barcelona and Real Madrid are allowed to negotiate their own TV deals, which means they claim nearly half the total amount of TV money.
In a statement, the Spanish federation stressed that they remain open to dialogue with the government, who have yet to respond.
Spanish football writer Andy West looks at how the long-running dispute has reached this point - and what happens next.
Why has this happened?
Essentially, the suspension is the result of a power struggle over who runs Spanish football.
More specifically, it is the climax of a long-running dispute over the distribution of television revenue, which is currently heavily weighted in favour of the 'Big Two' of Barcelona and Real Madrid.
Even Barca and Real reluctantly accept the mechanism should change, and last week it appeared the saga was ending when the LFP and the Spanish government announced a new law to introduce a collective bargaining agreement, similar to the English Premier League's.
But now the Spanish Football Federation (RFEF) have intervened because they are unhappy with some terms of the new deal and feel their authority is being undermined by not being involved enough in determining the finer points - they called it a "lack of respect" and claimed they were being "ignored".
The RFEF runs the sport in Spain, and has shown its disapproval by taking the ultimate step of picking up the ball and refusing to play, suspending all competitions at all age levels.
Perhaps the easiest way for British fans to understand the dispute is to liken it to the occasional power struggle that breaks out between the English Football Association (in Spain's case, the RFEF) and the Premier League (the LFP).
We could think back, even, to when the Premier League was formed in 1992 after breaking with the Football League and imagine what would have happened if the FA, rather than allowing the split to take place, had simply stopped all football from being played until they were satisfied with the outcome.
|Who is involved?|
|LFP (The National Professional Football League) - Responsible for running Spain's top-two professional divisions||RFEF (Spanish Football Federation) - Spain's football governing body, equivalent to the Football Association in England|
|AFE (Spanish players' association) - Represents the interests of Spanish footballers||Spanish government|
What are the players saying?
That is another complication: even before the RFEF's announcement, the players' association (AFE) had already threatened to launch a strike on the same weekend because they are also unhappy with the proposals for a number of reasons.
Perhaps most significantly, they believe the proposed split of money between the first and second divisions is not generous enough in favour of lower-ranked clubs, and that it will only serve to further widen the wage gap between top professionals and their lesser-paid counterparts.
That is a significant consideration because a number of Segunda Division clubs are already facing major financial problems which end up directly affecting players.
For example, last season players at Racing Santander forfeited their Spanish Cup quarter-final against Real Sociedad as a protest against unpaid wages. Their fans gave them a standing ovation, even though it meant they were out of the cup.
It's serious stuff. Mortgages and livelihoods are at stake because most players in Spain earn nowhere near the amounts that English Premier League and even Championship players can command - which is why so many of them head over to England every transfer window.
And the players feel that although top-flight clubs would benefit from the new deal, their brethren, already struggling in the lower tier, would face an even more uncertain future.
So it is essentially the government and the league against the players and the federation, making it much more difficult to find a quick solution.
Esteban Granero, ex Real Madrid and QPR, now at Real Sociedad said: "Footballers are on the side of our union. Everything should be solved without conflict and I think there will be an agreement."
Álvaro González, Espanyol tweeted: "All my support for the AFE. We are with you!"
While lower league players also voiced their support, Javi Selvas, of CD Castellon said: "Modest footballers need you, AFE, because you are fighting for our rights."
Javi Casares, of Hercules said: "We have to all fight together. The AFE are the ones showing face for us." While Fran Melli of Madridejos added: "We are all fighting together for our rights - minimum salaries and equality of treatment in football."
Is this for real - or just posturing?
It is very real.
It is also not an action that the RFEF has taken lightly, because even the showcase occasion of their own competition - the Copa del Rey final between Barcelona and Athletic Bilbao, scheduled for Saturday, 30 May - is now under threat.
Another danger, and an explicit threat in the RFEF's action, is that governmental interference in football's administration is prohibited by the game's global body, FIFA.
The RFEF is suggesting that the Spanish government is doing just that, which could, in a worst case scenario, see Spain banned from international competitions.
And the prospect of FIFA's involvement is made more likely by the fact that the RFEF's president, Angel Maria Villar, also happens to be a FIFA vice-president and a long-time ally of Sepp Blatter.
There are sure to be plenty of behind-closed-doors discussions between and amongst the four parties - league, federation, government and players - in the next few days.
The LFP have already called an extraordinary meeting of all clubs next Monday to discuss the crisis, but what really needs to happen is for everyone involved to sit around the same table together. And as yet, there's no sign of that happening.
Ernesto Valverde, coach of Athletic Bilbao (Copa del Rey finalists) said: "The threat is there. We don't know whether it's a measure to exert pressure or if it could be something more serious."
What's the reaction in Spain?
At the Nou Camp on Wednesday night I asked a senior journalist at a Barcelona-based newspaper whether he thought the league would really be suspended, and his initial reaction was to scoff and laugh: "No! Of course not!"
But then he reflected for a couple of seconds, a worried look spread across his face and he added hesitantly: "Well, actually…maybe. I don't know."
That sums up how the situation is too volatile to be predicted with any confidence. But fans, naturally, are outraged by the prospect of an exciting title race, which is currently set to go down to the final day, being disrupted by a political power struggle.
Villar is being cast as the villain and has little public support, but LFP chief Javier Tebas is also unpopular with fans - ironically enough, largely because he has allowed television companies to stage games at anti-social times.
The timing of the announcement - just before Barcelona took the field to face Bayern Munich in the Champions League semi-final - means that it sneaked somewhat under the radar in terms of the national media.
But once their dissection of Lionel Messi's latest heroics is over, it's more than likely that the blame will be squarely laid at the door of the power struggle between Villar and Tebas.
Will the season really be left incomplete?
|Key remaining fixtures|
|Sunday 17 May: Atletico Madrid v Barcelona; Espanyol v Real Madrid|
|Saturday 23 May: Barcelona v Deportivo; Real Madrid v Getafe|
|Saturday 30 May: Copa del Rey final - Athletic Bilbao v Barcelona|
Ending the season without champions is pretty much unthinkable and the matter will surely be resolved in due course - there is too much money at stake, for starters, for that not to happen.
And as the most directly affected clubs are Real Madrid and Barcelona, who carry enormous emotional, cultural and political sway throughout Spain, it's unlikely they would allow the situation to remain unresolved.
If there is any disruption, it is more likely that fixtures will be delayed rather than completely abandoned.
The weekend of May 16/17 is under genuine threat, but beyond that there is still plenty of time to fit in two more midweek rounds of fixtures, if necessary, before the end of the European season on Saturday, 6 June, when the Champions League final takes place.
The league has to be finished before that date because it is immediately followed by the South American national team tournament, the Copa America in Chile, which will feature leading La Liga stars such as Messi, Neymar and James Rodriguez.
But Spanish administrators can be stubborn and inflexible, prone to hiding behind legal jargon to protect their positions - as demonstrated recently by the Spanish government's refusal to even discuss Catalan demands for independence because it would be anti-constitutional.
So although the fuss will probably be cleared up in good enough time to finish the season, nothing can be taken for granted.