Rapoport also reported Goff suffered a dislocation:
Silver added the injury, which will reportedly require surgery, could end the signal-caller's season.
After Sunday's game, Rams coach Sean McVay declined to comment on Goff's status for Week 17.
"I'm not sure right now. I don't want to speculate on that," McVay told reporters. "I know he battled, and I have a lot of respect for the toughness that he exuded today to be able to finish that game out."
ESPN's Adam Schefter noted the quarterback is expected to undergo further testing:
Adam Schefter @AdamSchefter
Rams are uncertain if Jared Goff will be able to play in next week’s regular-season finale after he inured his right thumb during today’s loss to Seattle, per sources. Goff will undergo further testing after Rams return to LA. But there are concerns about his thumb’s condition.
Though he's uncertain of his status for Week 17, Goff noted that the injury isn't "terrible."
"It's OK right now. It's not terrible," Goff said after the game. "We'll see tomorrow. We'll evaluate tomorrow."
Any significant injury could be devastating for the Rams as they try to clinch a playoff spot.
It's especially damaging with no one else with legitimate NFL experience on the roster. John Wolford should take snaps under center while trying to keep Los Angeles afloat.
While inconsistency is a question mark for Goff, the starter led the Rams to the Super Bowl two years ago before losing to the New England Patriots in the final game of the year.
He has also performed well at an individual level, earning two Pro Bowl selections in the last three years. Though he was up and down in 2019, he ranked third in the NFL with 4,638 passing yards while adding 22 touchdowns.
The 26-year-old has played well at times in 2020 and entered Sunday with 3,718 passing yards, 20 touchdown throws and 12 interceptions.
McVay will hope his creative offense will be enough to keep the team afloat until Goff is 100 percent.