Spain easier to represent than Brazil, says Luis
Luis debuted for the South American nation in 2009, despite eligibility to represent both Spain and Poland.
The Atletico Madrid left-back had a dig at the national team where he resides, claiming Brazil have more depth in more positions than World Cup and European champions Spain.
"Yes. In Spain we have Jordi Alba, Nacho Monreal and Alberto Moreno," Luis told ESPN.
"On the right are Cesar Azpilicueta, Alvaro Arbeloa and Juanfran.
"In Brazil we can easily talk about 10 left-backs and 10 right-backs without opening the book.
"Marcelo, for me, is the best full-back in the world. I've learned a lot from seeing him in training.
"Then there's Maxwell, who's won everything. I wouldn't put myself ahead of anyone."
Furthermore, Luis said he had no regrets at deciding to snub Vicente Del Bosque's champions, claiming a Brazil cap is worth more to him.
"A call up to the Brazil team is worth 10 or 20 of any other country," he said.