Rodrigo, formerly of Bolton Wanderers, has had a mixed return to the Premier League.
But Orta told Marca: "He is the most expensive, of course. Everyone told me it was impossible and that motivated me more. We explained it very well to the player, we moved, we convinced him."
Along with Rodrigo, fellow Spaniards Kiko Casilla, Diego Llorente and Pablo Hernández are also on the books.
Orta continued: "I like quality, I don't look at nationality. We have Germans, Italians, Portuguese… There are mostly English because I love how these players work on a day-to-day basis. They are obedient. That is why I always thought that (Marcelo) Bielsa's way of working would work well with a large core of English players.
"And they drag the others to work. I always give an example: if a coach tells an English footballer to jump off a bridge into a river of frozen water, he first jumps and from below, asks why he had to do it. If it is of another nationality, first ask or do not do it. In England there is still respect for the coach."