Around 11am San Juan police responded to the shooting just feet away from their police department building.
Tony Saldana was standing nearby when he heard a loud bang.
"We rushed over to the man and he said he felt like he was hit by something so we check him and he was bleeding at the ankle," Saldana said.
Police said the man was a rushed to hospital for non-life threatening injuries.
Jose Alaniz was holding a campaign sign close to where the 55-year-old was shot.
"Of course we have to worry about our safety but sometimes you have a gamble, we leave and stop campaigning thats a no no we have to continue what we started and finish what we started," he said.
Police say the victim was holding a sign for Hector Mendez, who is running for constable.
At this time police don't think the shooting was politically motivated.
Police are currently on the lookout for the suspect they believe was driving a red pick up truck.