49ers star DE Nick Bosa (knee) to undergo testing

(Photo credit: Cary Edmondson-Imagn Images)

San Francisco 49ers standout defensive end Nick Bosa injured a knee during Sunday's victory over the Arizona Cardinals and will undergo further evaluation.

San Francisco coach Kyle Shanahan said the seriousness of the injury isn't yet known.

'No, we can't rule anything out,' Shanahan said after the 16-15 victory. 'They checked for ACL and stuff there. He was