Still unbeaten since Lopetegui arrived after the 2016 European Championship, Spain will go to Russia trying to rebound from disappointments in the last two major soccer tournaments — eliminated in the group stage of the 2014 World Cup and the last 16 at Euro 2016.
Lopetegui has called up more than 10 strikers since his arrival, with the most recent list including Diego Costa, Iago Aspas, Rodrigo and Lucas Vázquez.
Álvaro Morata, José Callejón and Vitolo had been regulars in previous lists but were left out of the important pre-World Cup friendlies.
Costa hadn't been called up in more than nine months because he couldn't play with Atlético Madrid until the team's transfer ban from FIFA ended in January, while Vázquez hadn't made Lopetegui's list since last year. Aspas has been a regular name in Lopetegui's teams even though he hasn't played much as a starter.
Morata was left out of the current list because of physical problems but Lopetegui said the Chelsea player still has a good chance of making it to Russia.
Among the other forwards tested by Lopetegui are Nolito, Paco Alcácer, Pedro, Aritz Aduriz, Gerard Deulofeu and even 36-year-old veteran David Villa.
They have had few opportunities recently, though, and are considered a long shot to make it to Russia even though Lopetegui said he hasn't closed the door on anybody.
"Some players were not included in this (last) list but they still remain with their chances intact," Lopetegui said. "All players still have chances."
A few attacking midfielders seem to have their spots secured after several call-ups under Lopetegui, including Isco, Marco Asensio, Saul and David Silva.
Silva is among the players with the most minutes in Lopetegui's team, along with Sergio Busquets and goalkeeper David De Gea. Silva also has the most goals scored under Lopetegui with 11, followed by Morata with seven.
Busquets, Thiago Alcántara, Koke and Andrés Iniesta are practically assured of a spot at the World Cup, which will likely be the last for Iniesta.
The 33-year-old Barcelona player has been struggling with his physical condition in recent months and hasn't played regularly with the Catalan club.
Busquets will miss the friendlies against Germany and Argentina because of a fractured finger in his foot but is expected to recover in time for the tournament in Russia.
It will also probably be the last World Cup for Gerard Piqué, who has said he plans to retire from the national team after playing in Russia.
Sergio Ramos will most likely be his teammate in central defence at the World Cup, with Jordi Alba and Dani Carvajal playing alongside them on the flanks.
Left-back Marcos Alonso got his first call-up for the upcoming friendlies and will be fighting to be in Lopetegui's final list.
"I'm getting a chance to show my worth," the Chelsea player said.
Calls for the return of Iker Casillas are long gone as De Gea continues to play in top form and is more than secured as the team's starter in Russia.
Kepa Arrizabalaga and Pepe Reina have been included in Lopetegui's most-recent lists and are expected to be the reserve goalkeepers.