A new biography of Walter Payton, the Chicago Bears’ late Hall of Fame running back, is drawing strong criticism from his former coach and teammates.

The book, “Sweetness: The Enigmatic Life of Walter Payton,” alleges that Payton abused pain-killers and nitrous oxide, considered suicide and for years kept a mistress. It goes on sale Oct. 4.

“I'd spit on him,” former Bears Coach Mike Ditka said of author Jeff Pearlman in an interview with Chicago’s NBC affiliate. “I have no respect for him.”

After battling liver disease, Payton died of bile duct cancer at the age of 45 in 1999. “If you're going to wait 12 years after somebody's passed, come on,” Ditka said in an interview on ESPN 1000. “This is the sign of a gutless individual who would do this. Totally gutless who would hide behind that, and that's what he's done.”

Ron Rivera, the Carolina Panthers coach who was a teammate of Payton’s, told ESPN 1000: “It’s unfortunate somebody wrote a book and throws that kind of light on somebody who's not here to defend himself . . . I think it's a shame.”

Pearlman said in an interview with 670 The Score in Chicago that he’d interviewed Ditka and urged people to consider the entire work.

“If you read the book, the whole book, it is much more sort of like the Vince Lombardi biography, ‘When Pride Still Mattered’ or the great [Roberto] Clemente biography by David Maraniss, than it is a slash job on Walter Payton, I guarantee you,” Pearlman said, adding that he knew none of the seamier details before he began writing. “But all people have is the excerpt. If you read the book — and people think, ‘Oh, he’s trying to make a buck,’ take it out from the library, stand in Barnes & Noble and read it, I don’t care — if you read the book, you’ll see it is a definitive biography of his entire life and this part of his life about his retirement, a very, very dark period in his life, is one part of the book.”

Another former teammate and business partner, Kevin Butler, said Payton’s behavior could have been caused by brain disease from all the hits he took. Another former ’85 Bear, Dave Duerson, committed suicide last winter and an examination of his brain showed signs of chronic traumatic encephalopathy.

“Walter delivered hits as much as he took hits,” Butler told the Chicago Tribune’s Fred Mitchell. “He was a throwback running back that you don’t have now because you beat yourself up. If a kid played like Walter did now, yeah, he would have concussion syndromes. He would beat his body down in a quicker rate because the athletes are just bigger and better now. Walter played a long, long time ... gained a lot of yards and took an awful lot of hits. So I would not be surprised if that kind of finding ... though it’s too late to know. Logic would tell you that he would fit right into that category.”

Still, his response doesn’t mean Butler approves of the book.

“I would just say, ‘why?’ ” Butler said. “What are you trying to accomplish?”

Gallery: The life of Walter Payton