49ers' Kyle Shanahan says Trent Williams in motion is scary to watch: 'I can't believe it's legal' | CBS Sports Headlines 49ers' Kyle Shanahan says Trent Williams in motion is scary to watch: 'I can't believe it's legal' The 49ers are going to keep lining Trent Williams up at fullback … Continue reading 49ers' Kyle Shanahan says Trent Williams in motion is scary to watch: 'I can't believe it's legal'