One deal has been done by the Blaugrana with Eredivisie giants, with highly-rated midfielder Frenkie de Jong set to complete a €75 million (£65m/$85m) switch over the summer.
It has been suggested that he will be joined at Camp Nou by a fellow Netherlands international, with Barca considered to be leading the chase for De Ligt.
They are, however, far from the only side to be monitoring the 19-year-old’s situation.
Mestra insists that those in Catalunya are yet to make any approach for a much sought-after talent, with Ernesto Valverde already boasting a wealth of centre-half options at his disposal.
"I don't know why they're saying this because [De Ligt] hasn't signed," Mestre told Sky. "[Gerard] Pique is evidently one of the best central defenders in the world, if not the best.
"After him, we have players like [Clement] Lenglet, [Samuel] Umtiti and we've signed a very young player in [Jean-Clair] Todibo. The defenders we already have are of the highest level.
"In De Ligt's case, we'll speak with the sporting director at the end of the season and we'll speak not about De Ligt, but about what they say."
While no approach has been made as yet, one may be in the offing.
Pique, meanwhile, is now 32 years of age and De Ligt would be a proven long-term successor to an iconic figure at Camp Nou.
A scramble for his signature is expected to be sparked, but it remains to be seen whether Barca will form part of that pursuit.