Barcelona forward Lionel Messi is a doubt for the first leg of the Spanish Super Cup after damaging a thigh muscle while on duty with Argentina and could miss the start of their La Liga defence, the European champions said on their website.
Barcelona visit Athletic Bilbao in the traditional curtain raiser to the season on Sunday, and could also be without Thierry Henry and Zlatan Ibrahimovic, who are recovering from injuries.
Messi's participation in Barca's first game of the Primera Liga season, at home to Sporting Gijon on August 31, is also uncertain because Argentina face Brazil at home in a World Cup qualifier five days later.
"I will ask permission from (coach Pep) Guardiola to be with my national team," Messi was quoted as saying in Spanish media on Friday.
Barca's first league game was moved due to the European Super Cup against Shakhtar Donetsk being scheduled for Friday Aug. 28.
Meanwhile, Bojan Krkic insists he feels no extra pressure about the prospect of leading Barcelona's attack in this Sunday's Spanish Supercopa first leg in the absence of a number of senior stars.
Although coach Pep Guardiola has yet to reveal his plans for the clash against Athletic Bilbao at San Mames, the 18-year-old forward looks set to start due to injury concerns surrounding Thierry Henry, Lionel Messi and Zlatan Ibrahimovic.
Bojan was largely used as a substitute during Barca's treble-winning success last season, but the teenager is not concerned about being asked to step into the breach for Sunday's clash against Athletic.
"There's no added pressure to be the starting striker at Barca. I've spent my whole life playing at this club," said Bojan, who scored one of the goals as Barca beat Athletic 4-1 to win last season's Copa del Rey final.
"Sunday's game is like any other where we'll be going for the win.
"Guardiola has not said anything to me, but if there are so many doubts then it is possible that I could be in the starting X1. (But) I hope that everyone's fit and we an enjoy playing together."
Bojan also spoke of his admiration for new signing Ibrahimovic.
Although Ibrahimovic has been unable to play a competitive match for Barca having undergone a hand operation the day after completing his 66million euro switch from Inter Milan, Bojan has seen enough of the giant striker to be impressed with the Swede.
"It's really great seeing him at first hand, how he plays and moves about the park," said Bojan.
"I need to learn a lot from him and from everyone else because they're not the best in the world for nothing.
"I always say that a footballer never stops learning. I'm almost 19 and I'm at the start of the learning curve, and even with the things I'm good at I try to do them better."