Fernando Llorente has admitted that Athletic Bilbao will struggle to replace Javi Martinez in midfield this season.
Martinez left the Basque club to sign for Bayern Munich this summer in a deal costing the German giants more than £30m.
Llorente believes that Bilbao must work harder to get results in order to compensate for losing such a key player.
He told reporters: "Javi Martinez is really an amazing player that gave many things to Athletic and is a very difficult player to replace.
"We have real good players who can do very well and trust them to do the work that Javi did last year."
The Spanish international has also been consistently linked with a transfer after his agent admitted that the striker is open to a January move to Italian giants Juventus.
