UPDATE: CAL FIRE SLO says the hiker is possibly dehydrated.
Emergency crews were responding to Cerro San Luis late Friday afternoon for reports of someone who fell on top of the mountain.
As of 4:45 p.m., CAL FIRE SLO said firefighters were were working to help the injured hiker off the mountain.
San Luis Obispo City Fire was assisting with its UTV.
The extent of any injuries was unknown.