The 25-year-old was left out of the setup for upcoming international friendlies against Germany and Argentina due to his lacklustre form at Stamford Bridge.
The forward has scored 13 goals in 38 appearances in all competitions and only one in his last 14 outings for the West London outfit.
"Of course Morata has a lot of possibilities to go to the World Cup and he knows it," Lopetegui told El Partidazo de COPE. "He has to show these months the player he is inside."
Morata joined the Blues from Real Madrid last summer.