Paul Giamatti revealed in an interview with Collider that he’ll be reprising his role as the Rhino in the third film, but not the fourth. This is what he said,
“I think I’m only doing the next movie, I don’t think I’m in the next-next movie.”
The interviewer then brought up Sinister Six, and he replied,
“They’ve not told me anything hard and fast about that.”
The third movie is set to be released on June 10th, 2016, and the fourth on May 4th, 2018.