The forward has signed a long-term deal with local rivals the Roosters from 2019.

Crichton has been criticised for his decision, but the 21-year-old is adamant he will do his very best in his last season for the Bunnies.

"There's never any lack of motivation for me," Crichton told NRL.com.

"We've got Greg's return to play, (Dane) Gagai's first year, John Sutton's possible last and 300 games, and it's the last year playing with Sammy Burgess.

"I'm excited to make 2018 the best I've had and work hard to make sure this year is the best I can make it for the Rabbitohs, and squeeze out as much as I can."

Crichton said his decision to join the Roosters was about doing what was best for himself.

"The thing for me is if the people I really care about – my family, players I will play with this year, the coaches and close mates – if they all understand where I'm coming from and what's going on with me then I'm happy," he said.

"I had to do what was best for myself."