Former Philadelphia Eagles center Jason Kelce apologized after he faced backlash for his theory former racehorse champion Secretariat was on steroids when the thoroughbred became the ninth Triple Crown winner in history.

During the May 8 edition of the “New Heights” podcast, which Jason co-hosts with his brother Travis Kelce, the former NFL offensive lineman cited Secretariat’s speed records when he claimed the horse was “juiced to the gills.”

He later doubled down on his claim by suggesting Secretariat’s “unparalleled muscular stature” was concerning.

“But the fact this horse had unparalleled muscular stature and died with an enlarged heart, and raced at a time when steroids were extremely prevalent, without adequate testing, raises flags in my book,” Kelce wrote in a social media post.

Jason Kelce (Andy Lewis/Icon Sportswire via Getty Images)

But he later walked back those claims, saying, “I’m sorry everyone, wasn’t trying to get people riled up,” Kelce wrote on X, formerly Twitter, May 9.

He added it was “unfair to assume these things publicly.”

A groom washes down American thoroughbred Secretariat (1970-1989) on the eve of the Belmont Stakes at Belmont Park in Elmont, N.Y., June 8, 1973. (Bettmann Archive/Getty Images)

“I really thought it was just known that in the 70s steroid use was rampant,” Kelce wrote. “I’m not trying to take away from Secretariat’s, or anyone from that eras legacy. You’re right, without proof it is unfair to assume these things publicly, I apologize.”

He then pointed to former Major League Baseball slugger Barry Bond’s past association with performance-enhancing drugs.

“I agree, that’s why I said the horses accomplishments are still Valid,” Kelce said, replying to a user on X. “We all know Bonds Juiced, he’s still the greatest hitter of all time in my opinion. He also did it against a large amount of players who were also juiced.”

Barry Bonds of the San Francisco Giants swings a weighted bat in the on-deck circle in a game against the Pittsburgh Pirates at PNC Park Aug. 13, 2007, in Pittsburgh. (Tom Szczerbowski/Getty Images)

Bonds was indicted by a federal grand jury on one count of obstruction of justice and multiple counts of perjury. In 2011, he was convicted on a count of obstruction of justice for providing incomplete answers during his testimony during the investigation into his alleged use of steroids. A federal appeals court overturned the conviction in 2015.

The jury did not reach a verdict on perjury counts.

Secretariat’s speed records in the Kentucky Derby, Preakness Stakes and Belmont Stakes have stood for more than half a century.