Nani was sent off in defeat to Real Madrid this week.
The Spain international told Mundo Deportivo: "Nani is going for the ball so I think it was very harsh. It changes the game; a red card should be for something much worse. There is so little between the big teams in Europe that a sending off makes so much difference.
"I always say with these incidents that you have to look at the intention of the player. Nani is looking at the ball and not at the defender. For me it is very harsh."