Cassel was intercepted twice by the Ravens, though both passes were tipped. He was also hit with two lost fumbles, one of them on a pitch that was mishandled by running back Cyrus Gray and the other on a flubbed exchange with Kansas City facing first-and-goal at the Baltimore 1.
"It's not right, you know what I'm saying? I'll speak that for any stadium, any player to get hurt," said Chiefs running back Jamaal Charles, who missed most of last season with a torn ACL.
"When someone gets booed, it's not right. It's his health. You know what I'm saying? He got hurt. You have to respect," Charles said. "It wasn't right that he got booed."
Once a Pro Bowl quarterback, Cassel is completing just 58.5 percent of his passes with five touchdowns and nine interceptions. He's averaging just 6.5 yards per pass attempt.
"I knew I hit him hard, but I didn't think it was hard enough to take him out. I thought I hit him right in the ribs," Ngata said. "Hopefully, he bounces back and gets better."
As for the cheering? Even the Ravens thought it uncouth.
"For them to cheer for him being hurt," Ngata said, "that's just not cool."