Sources said that while Chubb's ACL was stretched on the play, doctors do not believe the ligament is torn. Surgery is likely to happen this week, and sources said the hope is that more damage is not found.
Chubb's recovery timeline is expected to be six to eight months, sources said.
"I never would bet against Nick Chubb," one source said in relation to a quick recovery and comeback for the player.
Chubb, 27, injured his left knee after being hit following a 5-yard gain in the second quarter of Monday night's loss to the Pittsburgh Steelers.
The loss of the All-Pro running back for the rest of the season is a major blow for Cleveland, which spent part of the past week looking for replacements.
The Browns discussed trading for running back Cam Akers before he eventually was traded by the Los Angeles Rams to the Minnesota Vikings. Cleveland also considered signing Zonovan Knight off the Detroit Lions' practice squad, but it ultimately decided the best move was to bring back former Browns RB Kareem Hunt, who signed a one-year deal worth up to $4 million.
Hunt lives about 10 minutes from the Browns' complex, knows the offense and can step in Sunday to complement Jerome Ford. The Browns have big plans for Ford, whom the team believes also can be a threat with his receiving skills.
But one Browns official said the team went through an understandable grieving period this week before deciding they want to play for Chubb and not let him down.