Costa played two friendlies for the country of his birth in March 2013, but after a drawn out saga opted to represent the reigning world and European champions instead.
"I was going to summon him for the World Cup," Scolari was quoted as saying by O Estado de Sao Paulo.
"Diego Costa would be with us. He could play as a seven, a nine, or even as an 11. I’d thought about playing him up front to run and smash through. He’s a powerful beast. He's strong as a bull."Was I wrong? I don't know, but he would be at the World Cup with Brazil. I talked to him twice about it.
"The problem is there were other interests behind it. With Diego Costa becoming a naturalised Spaniard, that opened up his options in Europe. There's a whole set of interests."
Costa has made one appearance for Spain, playing 90 minutes in their 1-0 win over Italy in March, but the striker's World Cup campaign ironically hangs in the balance due to a hamstring injury.