Ronaldinho is disappointed with the Spanish football association's decision to uphold his one-match suspension following his sending off against Getafe last weekend.
The Brazil playmaker was shown a straight red card in the first half of the 1-0 win for kicking out at opponent David Belenguer following a foul by the Getafe defender.
Barca had appealed against the subsequent one-match ban, claiming Ronaldinho had been provoked, but the ruling was upheld by the Spanish Football Federation's Disciplinary Committee on Thursday.
Barca can appeal against that decision, but as things stand Ronaldinho will have to sit out the local derby with Espanyol on June 9.
"It is not fair. For me it is very important to play against Espanyol because of what we are playing for and it is a shame that it cannot happen," Ronaldinho said in Marca.
Barca are currently level with Real Madrid at the top of the Primera Liga standings on 72 points, although Madrid hold the upper hand due to their superior head-to-head record against Frank Rijkaard's two-time defending champions.
With only two games remaining Madrid will fancy their chances of claiming a first league title since 2003, but Ronaldinho insists he is only concentrating on Barca's plight.
"I am not interested in Madrid, the only thing I can say is that Barca are also confident and that we are to win the two games that remain," the former FIFA World Player of the Year said.