A person with knowledge of the trade tells The Associated Press that the Kansas City Chiefs have agreed to acquire quarterback Alex Smith from San Francisco.
The person spoke on condition of anonymity because the trade does not become official until March 12, when the NFL's new business year begins.
It's the first big player move by Kansas City since Andy Reid took over as coach after being fired by Philadelphia.
Fox Sports first reported the deal.
Smith lost his starting job to Colin Kaepernick after sustaining a concussion Nov. 11. Kaepernick played well, and coach Jim Harbaugh stuck with him even when Smith was healthy.
Kaepernick led the 49ers to the NFC championship and a close loss to Baltimore in the Super Bowl.