Abhishek Bachchan starrer Bob Biswas opened to mixed reviews and the general consensus that he should not have replaced Saswata Chatterjee, who originally played the character in Kahaani.

Saswata Chatterjee As Bob Biswas
Source: The Indian Express

However, while people continue to discuss the same, Chatterjee seems fine with the change. In an interview given to Hindustan Times, he said:

Why should I be disappointed? They are making it for the Hindi market; they will look for a bigger name. I did the film in 2012, why will I be bothered about it being made in 2021? I did several characters in between. If I was upset I would have come out and given so many statements. (But) I didn’t bother.

In fact, he said he was proud of the fact that Abhishek Bachchan played a character first portrayed by him and that he understands "what he has gone through".

I have full sympathy for Abhishek. I love Abhishek because even I’m a star son. So I understand what he has gone through his entire acting career.

Chatterjee further added perspective to the whole issue and explained how a single character can be played by two different people over the course of time.

When a character is played by two different people it should be played in two different ways. Say, James Bond. Every actor has played it differently and we should accept that. Bob has become a franchise like James Bond. So you should go to a movie hall with an open mind.

As for being approached by AB or director Sujoy Ghosh, his answer was a no. 

bob biswas
Source: Times of India

Well, that's one way of looking at things!