After an absence of almost a year, Mysterio returned on the July 16 episode of Raw, saving Zack Ryder from his old rival, Alberto Del Rio. On August 19 at SummerSlam, Mysterio unsuccessfully challenged The Miz for the Intercontinental Championship. During the match, Mysterio suffered a legitimate concussion, rendering him inactive for a week, but he returned to SmackDown on the August 31 episode. On September 16 at Night Of Champions, Mysterio failed again to capture the Intercontinental Championship from The Miz in a fatal four-way match, also involving Cody Rhodes and Sin Cara. The following night on Raw, Mysterio and Sin Cara teamed up to defeat Primo and Epico in a tag team match, after which they were attacked by The Prime Time Players (Darren Young and Titus O'Neil). According to Mysterio, he took the decision to leave WWE when he saw no creative direction about his tag team with Sin Cara. In October, Mysterio and Sin Cara entered a tournament to determine the number one contenders to the WWE Tag Team Championship, defeating Primo and Epico in the first round and the Prime Time Players in the semi-finals. Mysterio and Sin Cara were set to face the team of Cody Rhodes and Damien Sandow on the October 15 episode of Raw, but the match was postponed due to Mysterio legitimately suffering from effects of the stomach flu. The final took place the following week, on October 22, where he and Sin Cara were defeated by Rhodes and Sandow. On November 18 at the Survivor Series pay-per-view, Mysterio and Sin Cara were victorious in a 10-man elimination tag team match alongside Brodus Clay, Justin Gabriel, and Tyson Kidd against Primo, Epico, the Prime Time Players, and Tensai. On December 16 at TLC: Tables, Ladders & Chairs, Mysterio and Sin Cara were defeated by Team Rhodes Scholars (Cody Rhodes and Damien Sandow) in a number one contenders Table match for the WWE Tag Team Championship. Two days later on SmackDown, Mysterio was sidelined with a storyline injury when he and Sin Cara were attacked by The Shield. This was used to write them off television, as Mysterio was taking some time off, and Sin Cara underwent a knee surgery. Mysterio returned on January 27, 2013, at the Royal Rumble, entering the Royal Rumble at number fourteen but was eliminated by Wade Barrett. In March, Mysterio took another leave of absence due to a legitimate knee injury, explained in storyline as an attack by Mark Henry.