Spain coach Vicente del Bosque is concerned a long season may have taken a physical toll on his players but believes there is enough time for them to get in shape before the World Cup finals starts next month.
Most of the world and European champions' squad will be drawn from Barcelona, Real Madrid and Atletico Madrid and the three clubs were involved in a tense fight for the La Liga title that was only decided on the final day.
Real and Atletico are also through to Saturday's Champions League final and Del Bosque said both positives and negatives could be drawn from the situation.
"There is a bit of concern about the condition of the players, to see what shape they are in," Del Bosque said in an interview published on the official Spain website (www.sefutbol.com) on Friday.
"Around a third of the players in the squad will play this (Champions League) final," he added.
"The excitement that generates and being able to say we are playing this final I think are very important.
"In that sense, I think what we lose on the one hand we gain on the other."
Del Bosque is due to announce his final World Cup squad on Sunday and some of the players will meet up in Madrid on May 26 before being joined by those participating in the Champions League final on June 2.
"I am not a great fan of long training camps and I think we have enough time to prepare for the World Cup in the best possible way," Del Bosque said.
"You can never expect all the players to turn up in perfect shape and it's the same for all the national teams.
"All the players who are taking part in the World Cup have had seasons with a lot of tough games."
Del Bosque said he was confident forward Diego Costa and winger Jesus Navas would have recovered from muscle injuries in time to participate in Brazil.
He added that he believed the players, many of whom have won a glittering array of club and international trophies over the past six years, retained their hunger for success.
"I have confidence in them, the maximum possible confidence.
"If any player is distracted that is what we are there for to make sure they are focused on the fact that this is a unique opportunity to play at a World Cup.
"For the older players it is something extraordinary and for the younger ones there is no doubt that they will be very excited to take part. Let's see if we are capable of meeting the expectations.
Spain have been drawn in Group B with Netherlands, Chile and Australia and play their opening game against the Dutch on June 13 in a repeat of the 2010 final.