Cormier, the Strikeforce Heavyweight GP champion and a former Olympic wrestler, will make his light heavyweight debut after going 2-0 in the Octagon. In his last fight, Cormier (13-0) earned a unanimous decision over Roy Nelson on Oct. 19 at UFC 166 in Houston.
Cummins, who once fought under the Strikeforce banner, is 4-0 in his MMA career. In his last bout, he submitted Willie Smalls via guillotine choke at a Sparta Combat League event in May. A two-time All-American wrestler at Penn State, he was working his day job at a coffee shop when UFC president Dana White called him to discuss the fight.
"That's the fight business," White said Thursday. "Listen, if this guy is coming in and nobody knows him, whatever, and Cormier is who we think he is, he should smoke him then. If not, I don't know.
"I like it. You want to talk about a 'Rocky' story? This kid is the real Rocky. I like it."
Upon hearing about Evans' withdrawal, Cummins took to Twitter to campaign for the opportunity to face Cormier.
Evans pulled out of the bout because of a knee injury. He won the UFC light heavyweight title in December 2008 by stopping Forrest Griffin in Round 3 at UFC 92. He was knocked out in his first title defense, a second-round loss to Lyoto Machida in May 2009.
Evans was expected to miss only four weeks, but according to White the injury is more serious than originally thought and Evan is now expected to undergo surgery.
ESPN.com MMA reporter Brett Okamoto contributed to this report.