Cops say 22-year-old Daniel Elizarraras was at the legendary track Saturday in San Diego County where the horses were racing and a Cube concert was to follow.
People at the venue saw a string of sheriff's and police cars responding to the fairgrounds around 6:40 p.m.
Authorities said a man fired his gun near the race track and a deputy returned fire.
San Diego's FOX 5 reported that a San Diego Sheriff's Department deputy had shot a suspect near the racetrack entrance.
He was taken to Scripps Memorial Hospital La Jolla, SDSD reports.
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A video posted on Twitter appeared to show a man holding a handgun, with two deputies nearby. Just half an hour after the shooting, and with the day's racing finished, the racecourse tweeted that the gangsta rap gig would go ahead as planned.
The exchange of gunfire occurred just before Ice Cube was set to take the stage as part of Del Mar's Summer Concert Series, his performance set to be the last show of the summer schedule.
The announcer who is calling the race is heard saying, "There's gunfire at the track!".
As is our special events protocol, substantial law enforcement and private security was on site in anticipation of the event.
Ambulances and helicopters were also seen shortly after the shooting. "We will continue to fully cooperate with the Sherriff's Department in their investigation and will refer all questions concerning the incident to them", the statement continued.