Bears head coach Matt Nagy confirmed the news Monday after Cohen underwent testing on the injury.
"You love the kid. He's worked hard to get to this point," Nagy said. "We'll be in his corner and he'll be in our corner."
Cohen came into his rookie campaign without much hype after the Bears selected him out of North Carolina A&T in the fourth round of the 2017 draft. He's developed into a key contributor in a multifaceted role in which he recorded nearly as many catches (203) as carries (250) in his first three seasons.
The 5'6", 194-pound back has showcased terrific durability. He appeared in 46 of a possible 47 contests during his time with the Aggies and didn't miss any games with the Bears before this season.
David Montgomery figures to remain in the leading role, but Ryan Nall should also receive touches as part of the backfield rotation.
The emergence of Cohen as a contributor, especially on third down, makes this a more prominent setback.