UPDATED 10/18, 1:08 p.m. ET: Team sources tell the NFL's Ian Rapaport that an MRI confirms Mahomes sustained a dislocated knee cap.
The reigning MVP will seek second opinions, but it is likely he will return this season after being sidelined for a short period.
See original story below.
A cart was brought out for the 24-year-old quarterback but he was able to walk off on his own. Matt Moore took Mahomes' place.
James Palmer of NFL Media reports that Mahomes' patella was dislocated while ESPN's Adam Schefter reports a source as saying the team "will not know more until" an MRI is done.
According to Schefter, MRI results should be arriving Friday.
People have been taking to Twitter to wish Mahomes a speedy recovery.