Barcelona boss Ernesto Valverde says that he doesn't know much about Gremio starlet Arthur Melo but is well aware of speculation linking the Brazil midfielder with a January move to the Nou Camp.

Arthur, 21, has emerged as a target for the La Liga leaders ahead of the upcoming transfer window with the Catalans on the hunt for a new creative midfielder.

Earlier this month it emerged that Barcelona technical secretary Robert Fernandez had even travelled to South America to watch him in action during the Copa Libertadores final between Gremio and Lanus.

And the saga moved on over the weekend after a photograph of Arthur Melo wearing a Barcelona shirt alongside Fernandez was leaked through social media.

The La Liga giants were forced to issue an apology after Gremio president Romildo Bolzan expressed his disappointment with Barcelona, warning they will demand Arthur's full €50m (£44.2m, $59.1m) release clause should any suitor firm up their interest.

The midfielder later confirmed that he met with Barcelona officials but made it clear he is yet to sign any deal to join Valverde's side.

"Regarding the Barcelona issue, they really spoke with me. We had a meeting but I want to say that there is nothing closed, there is nothing defined. I did not sign anything. I'm a Gremio player, "Arthur explained.

"We have not started the negotiations. Then, if I sign the contract, I will be a Barcelona player, but this has not happened. It has to be something good for me and good for Gremio, which is my home. It's a club that I admire a lot, I came here with 14 years. I'm a gremista at heart, my blood is blue. It was only a first contact for them to know my family and for me to meet them. Let's take it easy. There is nothing defined but we did have a conversation."

Valverde is aware of the speculation but the Barcelona boss was coy over the possibility of adding the midfielder to his squad ahead of the second part of the season.

"I know there have been a lot of controversy [regarding Arthur] but I have only heard it from the distance. But the truth is that I do not know the player very well and I can not comment too much about him," Valverde said in the press conference following the Catalans' 2-0 victory over Sporting CP on Tuesday night.

"Of course Barcelona are always attentive to all players that are in any market, in Brazil and Europe. The club are attentive to all these types of questions and this is one more. Whether [the transfer] will be completed or not, I do not know."

Recent reports in Spain have claimed that the Catalans could also sign Yerry Mina from Palmeiras with Valverde currently having only two centre-backs available in Gerard Pique and Thomas Vermaelen.

Samuel Umtiti has been ruled out for around two months due to injury while Javier Mascherano has been on the sidelines since suffering a hamstring blow during the last international break.

But Valverde has identified Sergio Busquets as an "emergency" replacement after the 29-year-old midfielder played at the heart of the back-line alongside Vermaelen during the second half of the Champions League win over Sporting.

"Busquets is player who can adapt to different positions in in midfield but equally he can play as a centre-back," Valverde said. "He can do it well there. It's not the first time he has played as a centre-back. We tried with him today and in case of emergency we could do it again. Given we have two centre halves injured than it's an option for us."