Rams receiver Cooper Kupp suffered a potentially serious knee injury on Sunday — a blow to a team that has stayed remarkably healthy on the way to a 9-1 start. Kupp went down in the fourth quarter of Los Angeles' win over Seattle clutching his left knee, which sidelined him for two games earlier this season when he was hurt on a horse-collar tackle at Denver. Coach Sean McVay said Kupp would have an MRI on Monday. "I don't think it's good," McVay said. "It's his knee. We'll get the MRI, but it doesn't look good right now." Kupp led the Rams last season with 869 yards receiving as a rookie.