Some eyebrows were raised recently when Randy Orton didn't join WWE on the yearly European tour following WrestleMania season. Well, now we know why Orton was absent, and that's where we begin our look at some of the biggest WWE headlines making the rounds for Friday, May 18. 

Randy Orton undergoes knee surgery

WWE.com dropped the news on Friday that Orton recently underwent successful surgery to repair a medial meniscus tear in his left knee. Orton spoke to WWE.com following the procedure, where he revealed that he has needed to get the work done since last year and was putting it off until now. 

"I've known I needed the surgery since late last year, but I've been waiting for the right time to get my knee cleaned out," Orton said. "Right now was the right time."  

With plans probably already in place for Orton at WrestleMania late last year, it's understandable to see where he held off until this down period following the biggest event of the year to undergo the surgery. Orton walked into WrestleMania 34 in New Orleans as the United States champion, losing the title in a Fatal Four-Way bout to Jinder Mahal. The third-generation star worked on the Backlash pay-per-view earlier this month, failing to reclaim the U.S. title when he challenged current champion Jeff Hardy. 

WWE didn't specify a timetable for Orton's return, but with a meniscus tear, he should be on the shelf for a few months as he rehabilitates. 

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More WWE news, rumors

  • Sticking with injury news, SmackDown Live commissioner Shane McMahon also underwent surgery recently. McMahon underwent a procedure to repair a hernia last Friday in New York. As you'll remember, McMahon's WrestleMania status was put into question when he suffered from a bout of diverticulitis in addition to the hernia while vacationing with his family. So, this means McMahon wrestled twice before he actually had the surgery performed (WrestleMania 34 and Greatest Royal Rumble), further proving that he's an insane human being. 
  • "Nature Boy" Ric Flair revealed on Twitter that he was forced to cancel scheduled appearances this weekend "due to a sudden illness." According to Pro Wrestling Sheet, Flair is currently battling a bad case of the flu. 
  • The final eight entrants for the upcoming United Kingdom Championship Tournament were announced on Friday. Among the biggest names of this reveal are current 205 Live superstar Drew Gulak, British star Travis Banks and Finn Balor protege Jordan Devlin. 
  • According to the Wrestling Observer Newsletter [subscription required and recommended], the reason for Ronda Rousey working tag team matches on the house shows recently as opposed to singles matches is because the company doesn't want to put too much on her plate too soon.