The scouser had not featured since the away win at Grimsby in February, and has been struggling with a hernia problem. He made only 12 appearances for Town this season.
Town boss Gary Peters said he did not want to stand in the popular defender's way, "Dave wants to try as hard as he can now to try and get a club sorted for next season.
"He hasn't been playing many games this season and has taken a guess that I won't be offering him a contract for next season and has asked if he can leave now to try and find a club," the gaffer told ShrewsWeb.
Meanwhile, another player whose Town career looks to be over is Liam Murray. The Town youth product has joined Conference basement side Leigh RMI until the end of the season. 19-year-old Murray has not appeared for Town's first team as yet.
But Peters does not seem interested in the player long term: "Liam Murray has gone out on loan to Leigh, to hopefully get some Conference football under his belt - if he does well then it will be great for him and maybe give him a chance at somewhere else nest season," confirmed the boss.