The Spanish footballers' union was already threatening a strike, because the new TV deal, unlike that of the Premier league, doesn't include a few percent for the footballers themselves. Now the RFEF (Spanish football federation, comparable to the FA) has decided it's not happy either and is calling for an "indefinite suspension of all competitions" beginning May 16.
The reasons they give are the fact the RFEF no longer gets a percentage of the pools (quiniela) money, which they used to; an Entrepreneurs' Act which they say has the effect of shackling amateur football, as well as tax inspections and so forth having the same effect, and more besides. The complete text of their media release is here.
Striking at the end of the season is actually a pretty good threat, since the relegation and promotion races are still going on and with clubs' and players' summer commitments, it's hard to see how the season could be prolonged to get in the extra matches. For now, we will await developments, as they say.