The striker believes that the departure of the Spain international has left a gap in the northerners' side, but they can still replicate their Europa League run of last season
The German club signed the versatile Spain international for €40million in August and former team-mate Llorente has admitted that the 24-year-old has left a hole in Los Leones' starting XI.
"Javi Martinez is an amazing player that gave many things to Athletic and is a very difficult player to replace," he explained.
"We have real good players who can do very well and trust them to do the work that Javi did last year."
Marcelo Bielsa's side are in Europa League action on Thursday as they travel to France to take on Olympique Lyonnais, and Llorente hopes that their memories of reaching the final of the competition in May will help them replicate that run this season.
"It was a beautiful Europa League and sends back many memories. We have had experiences that have made us grow and mature in all aspects and I hope that these experiences will help us get better and be a team getting stronger and more consistent.
"I think that playing with the intensity with which we did last season in those competitions, having no fear of any rival, can make us a match for anybody."
The Europa League has come under criticism from some quarters for not providing the same amount of entertainment as the Champions League, but Llorente believes having teams such as opponents Lyon will help boost the tournament's profile and his own side's performance.
"There are teams that make the competition even better looking and give it more popularity.
"Lyon are a classic team in the Champions League and that means that we also have more desire to play against them and demonstrate our level."