The European champions are believed to be confident of wrapping up a deal for the Belgium international later this week as he is due to arrive in the Spanish capital on Thursday.
Rather than discuss any potential deal for Courtois, though, Lopetegui instead focused on praising "phenomenal" Keylor Navas, who has been first choice at the Bernabeu for the past three seasons.
Asked for an update on Courtois following Madrid's 2-1 friendly win over Roma in the early hours of Wednesday morning, Lopetegui told reporters: "As I've said, I don't speak about players who do not belong to Real Madrid.
"I'll only speak about the ones who are at Real Madrid and today is no different. Did you see him today? Keylor is our goalkeeper. He's here. There is no other goalkeeper we can talk about. Keylor, Kiko [Casilla], Luca [Zidane] and [Andriy] Lunin are the ones I can speak about.
"Keylor is phenomenal. He's been phenomenal all pre-season. He's an extraordinary goalkeeper. He's delighted to be with Real Madrid and we're delighted to have him with us."
Navas has started Madrid's last two pre-season friendlies - wins over Juventus and more recently Roma.