Winger not to be offered new deal.Loanee Troy Hewitt will also play no further part in the U's run in, having returned to his parent club QPR.
"He's been a great professional in his time here but found it hard to break into the first team. I wish him all the best in his endeavours elsewhere and thank him for the hard work he put in here."
Revealed the news on Thursday afternoon, boss Dunne said: "It's never nice to have to tell a player he's no longer needed and that was the case with Jack."
Since signing in January, the twenty four year old's first team chances have been limited and he made just one start for Joe Dunne's side.
The U's have parted company with Jack Compton.