The Chelsea striker was left out for the upcoming friendlies against Germany and Argentina.
Morata scored his first goal of 2018 in Sunday's FA Cup quarter-final win over Leicester City. And Lopetegui wants to see the 24-year-old return to form before June.
"Of course Morata has a lot of possibilities to go to the World Cup and he knows it," he told El Partidazo de COPE on Monday.
"He has to show these months the player he is inside."