Saints quarterback Drew Brees has multiple rib fractures on both sides of his chest and a collapsed lung on the right side, according to ESPN's Ed Werder.
It remains unknown how much time Brees may miss with these injuries, which he reportedly suffered over two weeks. Werder reports Brees sustained two fractured ribs against the 49ers on Sunday and three others in Week 9 against the Buccaneers. His first three rib fractures were not seen on an X-ray until Monday, and Brees "has been advised to be cautious with the collapsed lung."
Earlier on Monday, NFL Network's Ian Rapoport reported that Brees had a rib contusion and could be out for some time in order to fully heal from the injury. Brees did not play in the second half of Sunday's game after he was injured midway through the second quarter. The 41-year-old quarterback took a sack from Kentavius Street and remained in the first half, but he informed coaches at halftime that he was unable to continue.
After the game, coach Sean Payton said Brees would undergo an MRI and X-rays to assess the severity of the injury.
"He took a heavy shot in the first half. As he came out in the second half, he felt it was really impacting him," Payton told reporters. "As he tried to throw, he just came up to me and said, 'Hey, I don't feel like I'm capable of playing.' And so, quickly, we made the switch and, you know, that happens sometimes.
"He felt strong enough about letting me know and I know when he does that, which is probably gonna be the first time in 15 years, that it was significant enough where he felt like he couldn't function in the second half."
Brees was 8-for-13 for 76 yards and a touchdown before leaving the game.
"I was not going to be able to be effective," Brees said of the injury. "It had nothing to do with pain. It was simply just what my body was going to be able to do or not be able to do."
Brees was replaced by Jameis Winston, who went 6-for-10 for 63 yards. Taysom Hill also took snaps at quarterback but did not attempt a pass in the second half. The Saints beat the 49ers 27–13.