The midfielder says he wants to see the Bernabeu side lift La Liga this season but admits a defeat to his current club will make that goal more difficult
Granero left the Bernabeu in the summer of 2012 to join QPR before the Spaniard was loaned out to Sociedad after the English side were relegated from the Premier League.
Madrid-born Granero says he hopes to see his former side win La Liga, which is topped by their rivals Atletico ahead of Barcelona and Carlo Ancelotti's side.
Granero has been sidelined since September last year with a knee injury and is pleased to be returning against a club that means so much to him.
"I would like to see Madrid as champions but losing to us would complicate things for them," the 26-year-old said.
"It's special to come back from injuries against this opponent and it will be more emotional.
"I feel good. I'm ready to play and it's up to the coach. He makes the decisions."
Granero is desperate to get back playing as Sociedad look to qualify for the Europa League, currently sitting sixth in the table, a point ahead of Villarreal.
He continued: "We've done all kinds of tests, I feel fine and my rhythm is good, but now I need to play and the sooner I can do that, the better."