The NFL and NFLPA announced Sunday they will initiate a review of the handling of a helmet-to-helmet hit on Carolina quarterback Cam Newton in Thursday night's loss to the Broncos.

The NFLPA announced it would seek a compliance investigation.

The NFL later announced they would also initiate a review of the medical team's response to the hit on Newton.

Newton took at least four helmet-to-helmet hits in Thursday night's 21-20 loss, including one on Carolina's final series. Only one penalty was called.

Medical officials went on the field Thursday night to check Newton after that final helmet-to-helmet hit and determined he showed no signs of a concussion.