Asenjo hasn't played five Liga games for Valladolid this term and so can join Barca in January as a direct replacement for crocked reserve keeper Alberto Jorquera.
Also in Barca's favour is Asenjo's friendship with Bojan Krkic which could clinch his signing in their favour.
Asenjo's agent, Fernando Redondo, said: "The goalkeeper would be delighted to go to Barca, because they're a club that wants to challenge for everything. But he is conscious that he has a lot to learn and only thinks about progressing at Valladolid."