Adam Jackson has left the Imps following the cancellation of his contract by mutual consent.
The agreement means the defender becomes a free agent and can sign for another EFL club outside the transfer window.
Jackson joined the Imps in the summer of 2020 and went on to make more than 150 appearances across all competitions during his time at the club.
He played an important role throughout his time in Lincolnshire, including playing in the team that reached the League One play-off final in 2021 and helping City secure promotion to the Sky Bet Championship as League One champions during the 2025/26 campaign.
Sporting director Jez George said: “It is rare in modern football for any player to spend six full seasons at a club, but Jacko has made Lincoln City his home and represented us fantastically well, on and off the pitch. This decision hasn’t been made in the last 24 hours: it has just been executed in the last 24 hours, so that Jacko had the longest timeframe to join a club on loan in this window. When it became apparent that a suitable and mutually agreeable loan wouldn't happen, this was the best scenario for Jacko, having told him early in the summer that he wouldn’t be part of our 25-man squad for the Championship. In becoming a free agent as we come out of the transfer window, it means that Jacko can sign for any EFL club at any time between now and January.
“In the meantime, Jacko will continue to train with us so that we can help him maintain his fitness ahead of any possible move. That shows the respect both parties have for each other, and that we will do anything to help Jacko with what comes next in his career. He leaves us with huge respect, recognition for his contribution to Lincoln City over six years, our gratitude for his professionalism throughout and our sincere best wishes for him and his young family in the future.”