Middlesbrough chairman Steve Gibson insists Afonso Alves has talent, but accepts the striker's return of four goals this season was not enough.
Alves is Boro's record signing after arriving at the Riverside from Heerenveen for £12million in January 2008, but he has netted just 10 goals in 42 Premier League appearances.
He was on target just four times this term as Boro succumbed to relegation, but Gibson has defended the club's decision to purchase the Brazilian.
"He would be the first to admit that the season hasn't gone the way he would have hoped," said Gibson.
"It hasn't been through lack of effort, it hasn't been through lack of commitment to the club, it's just not happened for him.
"Every supporter I speak to sees something in Alves, that there is a talent in there, and it is whether we can get it out.
"We felt he could do it in the Premier League. He showed signs of that in the latter part of last season.
"It hasn't worked out for him. He has got himself into some great goalscoring opportunities, but he has only scored four goals.
"Now, I don't want to talk about individual players, but for any striker in the Premier League, four goals is not enough.
"Before that, he has scored 45 goals in 39 games for Heerenveen, and he got six in six for us last season."
Gibson was questioned about the homework Boro did before they made their move for Alves, but insisted they had not been the first club to have problems integrating an overseas player into the English game.
He said: "When we signed Alves, we had worked very hard on him.
"We had watched him play, but there is always a gamble in asking players to move from the continent into Premier League football.
"If you look at every club in the Premier League, they will have a story to tell on players who haven't worked out."