"I'm tired of pretending Ashton doesn't suck," Sheen told TMZ in a live telephone interview Thursday.
"I'm tired of lying. I'm tired of pretending the show doesn't suck. I'm tired of pretending Ashton doesn't suck," he explained. "It's nothing personal. I just feel bad for him. He's saddled with such bad writing."
Sheen's outburst came about a month after he ripped the show's writing.
"I don't think that [Kutcher's] working with the best writing because [producer] Chuck [Lorre] is doing too many shows," he told the New York Post at an event in January where he was trying to sell his new show, "Anger Management." "He and Jon [Cryer] and Angus [T. Jones] deserve better material. They deserve what I had for the first five years. I don't want to harp on them. Let the clueless stay clueless."
Sheen did have some compassion for Kutcher at that event.
"I've done what he's done," Sheen said. "I've replaced a guy [Michael J. Fox on 'Spin City']. It's so f***ing hard, you can't believe it," he said. "It's all you're thinking about, and you're surrounded by these ghosts. So, hats off to him for doing the best job that he can."
Sheen was television's highest-paid actor when he was fired from "Two and a Half Men" in 2011 after several drug and alcohol induced incidents, and after crossing its producer.