The decision brings to an end a highly successful two-year spell at Forest Green for the experienced 34-year-old forward, who finished both seasons at the top of the club’s goalscoring charts, playing an integral role in helping Rovers towards two play-off finishes.
He is now free to find a new club having netted an impressive 44 goals in all competitions from just under 100 appearances.
Signed from Fleetwood Town in July 2014, the former Stoke City and Hull City man had a stunning first season with the club. He scored 30 goals in total, including 25 in the league, to earn a place in the league`s team of the year.
He was also awarded with the Forest Green players’ player of the season, goal of the season and `golden boot`, as he helped them to the play-offs for the first time.
Last season Parkin again ended the campaign as leading marksman at the club with 14 goals in all competitions, while his final appearance came as a second half substitute in the Promotion Final loss against Grimsby Town at Wembley.
Commenting on his departure, manager Mark Cooper said: “Jon has been fantastic for the club and been great with me from the day I came in.
"I think he understands that his exit is just football, we need to evolve and change things a bit.
“He’s been great with the younger players and will continue to train with us for the rest of the week. I can’t speak highly enough about Jon."
Parkin's infectious personality and character made him a massive favourite in the changing room. Following the departure of Ady Pennock as manager at the end of last season, he stepped up to support caretaker boss Scott Bartlett in the dug-out during the play-off run that saw the club reach the final.