A witness posted video from near the entrance to the fairgrounds with audio of gunshots and video of police surrounding a man rolling on the ground.
Del Mar's final day of racing will begin at 2 p.m. tomorrow as scheduled.
"The racetrack has always been refuge from realities of our World, today shortly after last race at Del Mar Racing, several shots were fired yards from our TVG set during brawl outside Fountain admission gate", Schrupp wrote.
As the crowd panicked and fled, nearby deputies shot the man, leaving him lying on the sidewalk.
The department says in a news release that the man, whose name and age were not given, came to the ticket window at the Del Mar Fairgrounds about 6:40 p.m.
Sheriff's deputies responded by returning fire, hitting Elizarraras multiple times in the torso and arm.
Del Mar had invited fans who couldn't get in to the sold-out show to watch the concert on TVs throughout the track, including in the paddock area.
According to reports, 22-year-old Daniel Elizarraras attempted to purchase a ticket but was told that it was sold out. Elizarraras is in stable condition and expected to survive, the sheriff's department said.
The Ice Cube concert went on as planned. In light of the circumstances that unfolded involving one individual with a gun, we take consolation in the fact that no patrons, officers or security personnel were injured in the incident.
CBS 8 reported that two people were injured.