Reports emerged early on Wednesday morning that the Spanish FA felt "betrayed" by Lopetegui's decision to become Real Madrid's new manager following the tournament, having found out minutes before the announcement.
The news was made official later a few hours later, just a day before the World Cup's opening game and two days before Spain's first group game in which they face neighbours Portugal.
Reacting to the news on Twitter, Chelsea midfielder Fabregas joked that he may be a late addition to the squad having failed to earn a single call-up since Lopetegui's appointment after Euro 2016.
Wait, maybe I get a call up now! https://t.co/4InwsavXZa
— Cesc Fàbregas Soler (@cesc4official) June 13, 2018
Fabregas was replying to Gary Lineker's tweet, with the midfielder taking up a punditry role with the BBC for the duration.
Reacting to the news, Lineker tweeted: "Ah well, will give [Fabregas] something to talk about on his punditry debut."
Fabregas replied: "Wait, maybe I get a call up now!"
Spain can make changes to their squad in the wake of injuries up to within 24 hours of their first game.