Haas, a six-time PGA Tour victor and the son of professional golfer Jay Haas, was here for the Genesis Open, which will be played at Riviera Golf Course in Pacific Palisades starting Thursday.
While fire department officials did not provide the victims' names, Fischer told the affiliate that Haas, 35, was one of two people injured.
The Ferrari's driver was pronounced dead at the scene while Haas and a 50-year-old female were taken to hospital.
The crash involved a Ferrari and a BMW in the Pacific Palisades neighbourhood at 6.31pm on Tuesday evening (2.31am GMT on Wednesday), according to the Los Angeles Police Department.
Aside from the two vehicles directly involved, another Toyota SUV was sideswiped by the Ferrari just before the crash.
Details of the crash were updated on their website.
Haas is expected to be OK, according to multiple reports.
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But Haas, who's in stable condition, is "not good", a source told Golf Digest. Another vehicle suffered minor damage.
Haas, 35, was in a Ferrari that collided with a BMW.
"His vehicle basically just got clipped by the Ferrari", he said.
He began the week No. 67 in the official World Golf Ranking.
Jeff Fischer from LAPD yesterday told local TV station KTLA that Haas was "doing Okay".
The 2011 FedEx Cup champion was set to return to action on Thursday in the Genesis Open at L.A.'s Riviera Country Club.