Ferguson's manager Audie Attar of Paradigm Sports Management said Ferguson should be able to return to the Octagon by late May.
Attar said Ferguson's injury came from training and it was a "freak" thing, but not as serious as it sounds.
"You can either get it from something physical or respiratory infections," Attar told MMA Fighting at a UFC 199 media day Wednesday in Downtown LA. "It sounds scary, but it's not like, 'Whoa, you've gotta stop fighting, this is detrimental to your long-term health.'"
"I think it makes the most sense for Khabib to wait," Attar said. "I understand he hasn't fought in a while, so there's economic pressure on him. I respect that. If it was like months, I would say that would be a decisive factor."
The original fight was scheduled for April 16 in Tampa. Nurmagomedov (22-0) has not fought since April 2014 due to a series of knee injuries.
"[Ferguson] understands that he's waited this long already," Attar said. "He's empathetic to that as well as a fighter, no matter the rivalry."
LINK: Manager: Tony Ferguson targeting May return after healing 'freak' lung injury