The WWF itself would be missing some of its biggest stars, most notably Triple H, who tore his left quadriceps muscle on the May 21 episode of "Raw Is War", weeks before the start of the storyline and wouldn't return until the following year on the January 7 episode of "Raw", however he didn't compete as an in-ring competitor until the January 17 episode of "SmackDown!" in a tag team match and would also go on to win the main event a few days later at Royal Rumble 2002, well after the Invasion angle ended. Shawn Michaels, who was under a four-year retirement at the time, was on hiatus from WWF and also didn't appear during the Invasion storyline. Rikishi was inactive throughout the entire storyline with an injured shoulder, and didn't return to the WWF until December 2001. Eddie Guerrero and Chris Benoit who were former WCW/ECW stars, working for WWF at the time, were also absent from the storyline. Benoit was hinted to defect to WCW before his injury in June 2001 at King of the Ring. Guerrero was also hinted to defect to WCW but was sent to rehabilitation after an addiction with painkillers in May 2001 before being released that November. Both Guerrero and Benoit would not return to the company until April and July 2002 respectively. Dean Malenko and Perry Saturn, who were Benoit and Guerrero's former stablemates from The Radicalz were also absent from the storyline as well, with Malenko officially retiring from professional wrestling in July 2001 while Saturn was involved in a shoot incident during a "Jakked/Metal" taping and was minimally involved in the storyline; whenever Saturn appeared on match cards during the storyline, it is indicated that he is aligned with the WWF side.