William G. Baffert, the father of Hall of Fame trainer Bob Baffert, died Sept. 3. He was 88.
The younger Baffert announced his father's death via Twitter.
Bill Sr. died at his home in the U.S.-Mexico border town of Nogales, Ariz., according to Daily Racing Form.
No cause was given, although his son said recently that Bill Sr. had been in declining health.
Nicknamed "The Chief,'' Bill Sr. was the mentor for his son as a trainer. He was a rancher in Nogales, and used to race Quarter Horses on the Arizona fair circuit, with Bob riding many of them during his teenage years.
Based in Southern California, Bob Baffert won his 100th career stakes race at Del Mar last week, and has won the Kentucky Derby three times.
"Lost my first hero and mentor today. There's a new cowboy in Heaven," Baffert tweeted. "R.I.P. Chief. I miss you already."
Bill Sr.'s wife of 66 years, Ellie, died on June 23, 2011, after a long battle with cancer.
Besides Bob, Bill Sr. is survived by daughters Adrienne Braccia, Nori Van Buren and DeeDee Kirsch, and sons Bill Baffert Jr., P.A. Baffert, and Gamble Baffert. The couple had 21 grandchildren and eight great-grandchildren.