The former Spain boss knows that squad depth is important if you are going to challenge across various different competitions, hence his request.
According to the aforementioned source, Lopetegui's wishlist included a centre-back, a midfielder and a striker, with the latter the biggest priority.
Whilst many are backing Karim Benzema and Gareth Bale to step out from the shadow of Cristiano Ronaldo and shine this season, Lopetegui is seemingly keen on having a more reliable alternative at his disposal.
Several names are mentioned in the report, among them: Rodrigo, Icardi, Werner, Lewandowski and Mariano.
Whilst Lopetegui is thought to be willing to struggle on without additions in other areas he sees reinforcements up front as an absolute priority.
Interestingly, 'Marca' claims that Lopetegui has meade it clear that he doesn't care whether the addition is a big name, providing they can perform in the role asked of them.
However, it also stated that the Real Madrid hierarchy doesn't see adding a forward as a prime concern, with Mariano and Rodrigo's price tags considered too high to represent value for money.
Nevertheless, there is the potential to meet Lopetegui's request, providing the right deal emerges as the deadline approaches.