The actor said that he initially took on the part as a "two-hour voice job", claiming that it is "meaningless" to him.
"It was one of the only things I've ever done where I had no knowledge of it, I didn't care about it, I didn't think about it, he told Collider.
"They wanted me to do it. In one way, I regret that bit. I don't regret doing it, but I very rarely do something if it's meaningless. It was meaningless to me, honestly. I don't mean that in any nasty way. I did it."
Weaving, who said that he hasn't yet been approached to come back for Transformers 4, added that he has had little contact with franchise director Michael Bay.
"I have never met him. I was never on set. I've seen his face on Skype," he explained. "I know nothing about him, really. I just went in and did it. I never read the script. I just have my lines, and I don't know what they mean."
Recent rumours have suggested that Transformers 4 will revolve around a female protagonist.
According to director Bay, the sequel will pick up in Chicago straight after the events of Transformers: Dark of the Moon.