The 23-year-old was one of Colombia's standout performers at the World Cup, starting all five of his country's matches at the tournament, and while Racing Santander were already well aware of his qualities, that showing has pushed him onto the radar of clubs well beyond Spain.
He is under contract at El Sardinero until June 2029, though the scale of interest building across the continent means Racing face a genuine fight to keep hold of him.
According to Sebastião Sousa-Pinto, Nottingham Forest have made an approach for the midfielder as they look to strengthen a position weakened by Elliot Anderson's move to Manchester City, with Puerta said to be open to a return to English football having previously spent a loan spell at Hull City, making 30 Championship appearances.
Real Betis, Villarreal and Zenit St Petersburg have also been credited with interest, with the Russian side reported to be the most advanced admirers, though Racing are understood to be holding out for at least €20m.
Forest and Olympiacos share the same ownership group, led by Evangelos Marinakis, raising the possibility that Puerta could ultimately be loaned to the Greek club to continue his development if a deal with Forest is completed.
Puerta made 33 appearances and contributed three goals and two assists last season as Racing secured promotion to LaLiga, having joined from Bayer Leverkusen the previous year following a season on loan at Hull City in the Championship. FC Porto had also been credited with interest in the midfielder but are understood to have dropped out of the running given Racing's valuation, leaving Zenit as the frontrunners for now even as Forest continue their own enquiries.
Puerta began his career in his native Colombia at Bogotá before a move to Germany with Leverkusen, where a loan at 1. FC Nürnberg preceded his switch to English football with Hull, and he has since become a regular fixture for the senior Colombia squad after coming through the country's youth ranks.
Any deal, whichever club it involves, is expected to represent a significant fee for Racing, who are eager to build on last season's promotion without being forced into a sale before they have secured value that reflects his rising profile.