The 24-year-old joined the Dragons on a two-year loan in July 2014, and he has since showed a great deal of potential.
Barcelona officials do not think that he has a future at Camp Nou and are ready to cash in on his services, and they hope FC Porto will exercise the €8 million buy-out clause in his contract.
However, while the Dragons want to keep hold of the talented footballer, they are set to try and lower the asking price.
The two clubs will hold a series of meetings over the next few weeks in an attempt to reach an agreement, but it is important to note that clubs from English Premier League are keen on Tello as well.
Following the impressive triumph over Real Madrid in El Clasico, Barcelona are 4/25 favourites to lift the La Liga trophy.