Doctors believe the lung was punctured when he took a shot to the ribs at the end of the third round. He is being held an extra day at a local Phoenix hospital for observation, Butler said.
Felder defeated Vick by unanimous decision. Two of the judges scored the fight 29-28 and the other 30-27. It was his fourth win in his past five bouts.
The Philadelphia native was emotional in the Octagon after his victory, dedicating the result to his mother.
"Mom, I love you so much," Felder said. "You raised three crazy sons. You put up with our crazy father. And here I am. I won this one for you, Mom." Felder later turned his attention to the rest of the division. He said he will be watching the Justin Gaethje vs. Edson Barboza fight on March 30 very closely.
"I was told during the fighter meetings this week that I'm not intelligent enough, that I'm not well-rounded enough to win a decision," he said. "One-fifty-five [pounds], you better look out, because no matter how you want to get it, you're gonna get it."