Rua injured his left knee in May, possibly during his UFC 113 rematch with then-champ Lyoto Machida. He opted to have surgery on the knee the following month and has not fought since.
UFC president Dana White is targeting March 2011 for Rua-Evans, but that time frame is contingent on the champion being fully healthy. In the event Rua isn't ready at that time, White told ESPN.com he will look to hold the bout in May or June.
Eduardo Alonso, Rua's manager, does not intend to put his fighter back in the cage before he is 100 percent healthy. Rua won't begin full training until his doctor gives the OK.
The earliest Rua (19-4-0) will return to the Octagon is anyone's guess and Alonso refuses to speculate.
"It's tough to say right now, because we are not rushing things, and UFC has been very supportive, so the important thing to all of us is to have him properly recovered and in shape, as we can't make mistakes with the recovery," Alonso told ESPN.com. "We still have to see his doctor one more time before he can do everything we want in training, so it would be useless to talk about dates now."
This is unwelcome news for Evans, who earned the right to face Rua with a unanimous decision victory over Quinton "Rampage" Jackson on May 29. Evans has been waiting for an official fight date to be announced ever since.
But with Rua's return to action still in the air, Evans' patience is beginning to wear thin. As far as he is concerned the time has come for UFC to make something happen.
"It's just frustrating," Evans told ESPN.com. "I am a fighter and I need to make a living doing this, but at the same time it's about getting that gold.
"But if the gold is something that I'm not going to get an opportunity to fight for then I have to face that possibility and move forward and do some other things.
"If I don't get the chance to fight for the belt, I will never ask to fight for this belt again. I will never want to fight for that belt again."
When informed of Evans' stance, White was surprisingly calm. He took a deep breath and sighed.
"That's the weirdest comment I have ever heard in my life," White told ESPN.com "[Rashad] is scheduled to fight in March.
"We offered him a fight in September; he turned it down. He said he didn't want to harm his brand. I don't know what the Rashad Evans brand is, or what that means, but he said he didn't want to harm it. It's not like we were keeping him from fighting, he chose to wait for Shogun. It's not our fault; Shogun had knee surgery."
Evans doesn't deny receiving a fight offer in September from UFC officials, but says his focus has been solely on facing Rua.
But Evans' position of only wanting to fight Rua is softening. He is willing to face another opponent, if the fight has title implications. Evans finds an interim title bout appealing, and believes the UFC should consider making that option available to him.
"If they say that I can fight so-and-so for the interim title then it's something. I don't know," said Evans, who is 15-1-1.
"If [Rua] is going to be out longer than May or June then [UFC] should consider an interim title and I will fight for an interim belt. It's something.
"It might not mean much to everybody, but it's something. But if I don't get a chance to fight for an interim belt, then I will just beat everybody in the division and I will never fight for the belt."
Evans believes that creating an interim light heavyweight title bout makes the most sense at this time. Besides, he reasons, the UFC has taking this step previously when champions have been sidelined for extended periods.
"There have been other times when they've had situations like this and it's never happened like that," Evans said. "So if I don't get to fight for this belt because [Rua] stays injured too long and they don't make anything happen, then I will never ask to fight for that belt again, man.
"The main goal is to get the belt, but it seems the closer I get to the belt the further away it gets, like it's not going to happen. I understand that Rua is hurt, but they've been in situations like this before and have made it work."
White said Evans isn't knowledgeable of the criteria that would lead UFC to create an interim title belt. And the situation involving Rua doesn't meet those criteria.
"We created an interim title belt when he champ's future was absolutely unclear," White said. "We thought Brock Lesnar was going to need surgery.
"The guy who holds the belt is the champion. If he can't return for a long amount of time, and that amount of time is undetermined, then you create an interim belt.
"Personally, I have a great relationship with Rashad. He's a great guy. When you meet him outside, he's a great guy. But when it comes to fighting, he is a complete head case."
While it remains unclear just how soon Rua will be ready to defend his title, there is good news on his condition. It turns out the knee injury wasn't nearly as severe as first thought, and Rua's rehabilitation is progressing smoothly.
"The good news about his injury was that his kneecap, cartilage, meniscus, etc., were all preserved," Alonso said. "After the surgery the doctor was amazed, and mentioned his knee structure looked like the one of a 16-year-old, and he is doing a much better rehab this time than the other times.
"We had great support from the UFC and I'm sure he will be properly recovered."
Franklin McNeil covers MMA and boxing for ESPN.com. He also appears regularly on "MMA Live," which airs on ESPN2. Follow him on Twitter at www.twitter.com/Franklin_McNeil.