Clay Matthews was injured on this sack. (USATSI)

Packers linebacker Clay Matthews left last week's game against the Steelers after he reinjured his thumb, and the next day, coach Mike McCarthy said "The training staff didn't feel very good about the injury."

The training staff was apparently on to something, and in Green Bay's Wednesday injury report, the team announced Matthews is out for Sunday's game vs. the Bears.

It's not a surprise, but it's also a significant blow to a Packers team that needs to win in Chicago in order to take the NFC North title and make the postseason. At this point, it's still unclear whether quarterback Aaron Rodgers and his injured collarbone will play, but we should know the news for sure by Thursday.

Matthews originally broke his thumb in Week 5, and he missed the next four games. Against the Steelers, he reinjured the digit while sacking quarterback Ben Roethlisberger.

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