Aspas was speaking after their preseason 2-2 draw at West Ham on Saturday.
He said of Moriba: "He is a boy who has brutal conditions. We have to put him in group dynamics because he has been training with us for a short time. He has some characteristics that we did not have in the squad and it suits us to come in very well throughout the season."
The captain is also very satisfied with the team's preseason.
He said: "We have had very good feelings. It was already seen during the games, apart from the one against Lille in which we were not well adjusted for 25 minutes and they hurt us. We have faced equal rivals and we have competed very well."
Iago Aspas also thanked fans who have sold out the stadium for next Friday's LaLiga opener against Alavés.
"We are very happy. We are grateful. We saw last season how they encouraged us in bad times. We thank them and tell them that we are going to have an exciting season."