Although WBA have ordered a rematch according to his promoter, Petersen could decide to forfeit the title rather than hand Khan a second chance.
Amir Khan handed chance to put the record straight with Lamont Peterson
Richard Schaefer, chief executive of Golden Boy Promotions, reported overnight that the governing body have notified him of their "official decision" to order a rematch following the controversial bout last month.
Khan lost both his WBA and IBF titles in a split decision defeat in Peterson's Washington DC hometown on December 10.
The Englishman has vociferously complained about a number of issues since then, however, and has lobbied both governing bodies - and the Washington DC commission - to change the result to a no-contest and/or force the two men to fight again.
Schaefer told RingTV they have got their wish.
"I just received, half an hour ago, a letter from the WBA on their official decision that they are going to order an immediate rematch," Schaefer is reported as saying.
"I think that it's the right decision, and I hope that we can get the rematch done."
Schaefer also told espn.com: "I'm thrilled that he's getting (the rematch) and hope we can start the negotiations and get the fight done.
"Amir and Lamont are both terrific young men and athletes who fought their hearts out in Washington in December and I'm sure this decision will get applause by fight fans around the world.
"The rematch will be one of the most anticipate fights of 2012 because both guys are exciting, young and I think it's exactly the kind of fight people want to see."
Khan's advisors initially claimed Peterson's team voluntarily agreed to a rematch in the immediate aftermath of the bout only to apparently change their minds.
And while the WBA have ordered the second fight, Peterson could still opt to relinquish that title rather than give Khan a second chance - particularly if the IBF, at a hearing on January 18, allow him to keep that belt without fighting Khan again.