Midfielder David Carson has left South Shields after a "deterioration" in his relationship with the club's management.
Carson joined Shields in the summer after being released by Blackburn Rovers.
He had earlier spent time in the Northern League with Ashington and Jarrow Roofing, and was also on the books of Newcastle United and Sunderland as a youngster.
The 21-year-old scored six goals in 28 appearances for the Mariners, and he is now free to find a new club.
A club statement said: "The club can confirm it has parted company with midfielder David Carson.
"The working relationship between management and the player had deteriorated recently, and it was decided it was in the best interests of both parties to go their separate ways.
"We wish David all the best in his future endeavours."