Middlesbrough boss Aitor Karanka is convinced Alvaro Negredo can reach his potential in England.
Karanka admits the powerful striker hasn't always hit the heights back in Spain.
But he reckons he will underline his class on his Premier League return, saying: “He's a good player and if he recovers his best form for us, then he will be a really important player for us.
“It's a real plus that he's played in England before and he knows the Premier League.
"He wants to do his best for us and he knows this is the best place to show what he can really do."