"Ashton has been rocked by the firing of his friend Danny," the insider said. "He doesn't want to believe any of the accusations against his longtime friend, but he does hope the truth will come out."
Masterson was fired by Netflix Monday after he wrapped up filming scenes for the comedy's second season. He and Kutcher have worked together on the show since its debut in 2016, and Kutcher also serves as executive producer.
"As one of the executives on the show, Ashton is agreeing to swift action being taken. He is trying to protect the show and jobs of others working on the project. He just feels horrible about the whole situation," the source added.
Many have been calling for the streaming service to terminate Masterson after four women claimed the actor raped them. But Netflix, who swiftly fired Kevin Spacey and Louis C.K. for similar allegations, stayed quiet until Monday.
"As a result of ongoing discussions, Netflix and the producers have written Danny Masterson out of ′The Ranch.′ Yesterday was his last day on the show, and production will resume in early 2018 without him," the streaming company wrote in a statement released Monday morning.
The 42-year-old's history of sexual assault accusations dates back to 2004, when a woman accused the That '70s Show actor of sexually assaulter her the year prior. The case failed to move forward after the Church of Scientology, of which Masterson is a member, submitted over 50 affidavits from Scientologists denying the woman's accusations. Since then, three other women have alleged that the actor sexually assaulted them in the 2000s.
Each of the women, who are linked to Scientology, allege that the Church shamed and pressured them to keeping quiet.