
Barca, for instance, have a crucial game away to Villarreal on Saturday. But will Ronaldinho be in condition to play, after turning out for Brazil on Sunday against Colombia and on Wednesday against Ecuador?
The playmaker is due to fly into Barcelona from Rio de Janeiro on Friday morning, a few hours before Barca leave for Villarreal.
Barca coach Frank Rijkaard is contemplating leaving Ronaldinho at home. But will Lionel Messi and Gabriel Milito be in better shape after playing twice for Argentina? And what about Thierry Henry and Eric Abidal after their exertions for France?
Last week Barca president Joan Laporta - after demanding "compensation" for the clubs from the national federations - advised his players to be careful with their efforts for their country. None of them appear to have heeded his advice.
To make matter worse, all of the big boys are playing on Saturday, in order to have more time to prepare for next week's Champions League games.
Leaders Real Madrid have a difficult game away to in-form Espanyol. Coach Bernd Schuster is crossing his fingers that Robinho has not taken many knocks for Brazil or Wesley Sneijder for the Netherlands.
The good news for Schuster is that Dutch manager Marco Van Basten didn't pick Real striker Ruud Van Nistelrooy against Slovenia on Wednesday. Neither was fellow-striker Raul Gonzalez picked by Spain.
Earlier on Saturday third-placed Valencia - seven of whose players were in the Spain squad - are away to Deportivo Coruna, while Sevilla face bottom team Levante, now under Italian coach Gianni De Blasi.
Sevilla are as much the victims of the so-called "FIFA Virus" as any club. Fabien Escude has worsened a recurrent thigh injury playing for France, Khalid Boulahrouz has returned from the Dutch training camp with a throat infection, Frederic Kanoute is still covered in bruises after last Saturday's stormy Togo-Mali clash.
Sevilla are desperate to get back to winning ways after four straight defeats - but will their international players have the necessary fitness and energy?
The big game on Sunday will see sixth-placed Atletico Madrid vs bogey team Zaragoza, who are eighth. Sunday's other games are as follows: Recreativo Huelva-Mallorca, Getafe-Murcia, Betis-Racing Santander, Valladolid-Athletic Bilbao and Almeria-Osasuna. By Duncan Shaw, dpa