He has started just once in the Premier League, despite choosing Tottenham over Chelsea who were also interested in him.
The Basque striker came through the ranks at Bilbao, and last summer he hinted that he would love to go back, saying: "Athletic Club are my home and if they make an offer, a return could happen.
"I enjoyed many wonderful moments at the club that I will never forget and Athletic will always hold a special place in my heart.
"If they do make me a proposal to come back, then I would have to think about it and yes, maybe it could happen."
Llorente has scored five times for Spurs this season, although three came against Rochdale in the FA Cup.