Transcript for Did Chiefs' Fans Cheer Matt Cassel's Injury?
We're going to turn, now, to the shocking moment at sunday's nfl game in kansas city. Some hometown fans actually cheered when the chief's quarterback was knocked flat And one of his teammates is fighting back, comparing the hecklers to the crowds at the coliseum in roam. And this sparked a lot of soul-searching in kansas city. A lot of people wondering what happened there. Kansas city fans critical of matt cassel's performance over the weekend. But when he took that hit, the fans' reaction may have crossed the line. A teammate, firing back. Cassel got drilled on the play. He's in real trouble here. He was rocked. Reporter: Embattled kansas city quarterback, matt cassel, was pummeled during sunday's chiefs/ravens game and lay motionless on ground, before leaving the game with a concussion. And while faint on tv, it sounded as if the home team's disgruntled fans were cheering the injury. I've never been more embarrassed in my life to play football than in that moment. Reporter: After the loss, his teammate, eric winston, lashed out. We have 70,000 people cheering that he got knocked out. I think it's sickening and disgusting. We are not gladiators. And this is not the roman coliseum. This is a game. Reporter: By monday afternoon, winston's off-the-cuff candor had gone viral. His rebuke being replayed and analyzed on our sister network, espn. Where's the civility? Where's the compassion? Reporter: What may be more surprising, this morning, kansas city fans are firing back. And not in solidarity with winston, but in anger. Accusing him of unfairly lumping hard-core chiefs loyalists with a few rude fans. You're saying I don't want this guy throwing a football for me anymore. wishing he was injured. Reporter: On twitter overnight, winston thanked supporters. Tweeting, I stand by what i said. I believe what I said. While admitting 70,000 fans may not have cheered the injury. But even one was one too many. Now, cassel is expected to miss the chiefs' next game against tampa bay this weekend. There were questions if people were clapping that heked off the field under his own power. Kansas city chiefs fans among the very best in the sport. Hard to believe that anybody was celebrating an injury. That is hard to believe. Josh, thanks so much.
This transcript has been automatically generated and may not be 100% accurate.