Lionel Messi
Lionel Messi is expected to miss the game against Valencia.Getty Images

Barcelona manager Luis Enrique has refused to set a deadline for the recovery of Lionel Messi after the Argentinian star underwent kidney surgery on Tuesday (9 February), just a day before the Copa del Rey second leg semi-final against Valencia. The boss, meanwhile, claimed that Rafinha Alcantara could become the club signing of the spring after the Brazilian midfielder had returned to training following more than four months on the sidelines.

Messi sparked fears over his participation in the Wednesday game against Valencia and the match with Celta Vigo on Sunday after missing Monday's training session, with reports later revealing that he needed to undergo a test regarding the kidney stones problems which prevented him for playing the Club World Cup match against Guangzhou Evergrande at the end of 2015.

The club later made an official statement to confirm the news while revealing Messi would be ready to return to training sessions on Wednesday.

"FC Barcelona striker Lionel Messi will undergo several tests on Monday and Tuesday to assess the evolution of the kidney problems he suffered last December. Messi will return to his normal duties with the first team on Wednesday," the club stated in an official statement.

But asked during the press conference ahead of the game against Valencia whether the Argentinian will be available to play the game or the next encounter with Celta, Luis Enrique said: "The club have released a medical report explaining the situation. What happens next is Leo's business. I have no further comment to make.

Rafinha, meanwhile, has been out of action since he suffered a tear to the anterior cruciate ligament in his right leg during the Champions League draw against Roma in September 2015. The 22-year-old Brazilian international was expected to miss much of the remaining of the season but surprisingly returned to the training pitch ahead of expected.

Enrique is still cautious about the versatile midfielder return to action but admitted that the recovery is going well and he may be ready to help the team in the last part of the campaign, being able to play both in midfield and in a more attacking role.

"He is not going to be a January signing but in any case a one for the spring season" the Barcelona manager said. "He still has about a month and half or to two months to go. No rush. Everything is going great; he's feeling good but we don't know if he'll be able to help us at the end of this season or whether he'll be back for the next one. You can't afford to rush injuries of this nature."

Luis Enrique is expected to rotate his squad for the second leg against Valencia with a number of young players, having a huge advantage after a trashing 7-0 victory at Camp Nou. The manager, nevertheless, refused to disclose his line-up while urging his side to not take anything for granted.

"In order to motivate players for such a big game, it's a challenge, it's a test for coaches to keep players competitive. But we've demonstrated it in the year-and-a-half that we've been here that the players can compete in any situation," the Barcelona boss added.

"I don't expect tomorrow to be any different. We'll try get the victory from the first minute. The objective will be the same as always, to try and be better than them. It's a strange game because of the first leg but there isn't such a huge difference between two teams as there was in the first leg. That is what happened and we'll try forget that result and approach the game in the best way to pass into the final."