Goalkeeper Rhys Evans, defender Kevin Amankwaah, midfielder Mark Molesley and striker Guillem Bauza will not be retained while negotiations are ongoing with key trio Matt Oakley, John O'Flynn and Jamie Cureton.
"Unfortunately I can't afford to keep them here," he told the club's official website.
"There are others that I'm in negotiations to keep, if I can find the right amount of money - Jamie Cureton, John O'Flynn and Matt Oakley are all players I would like to keep.
"Amankwaah was one of the toughest decisions I've had to make and one of the most difficult conversations I've had. He has been fantastic for us, so that has been particularly difficult.
"I've been impressed this year with Rhys Evans. He's definitely good enough to play league football and I'd have loved to have kept him.
"Guillem's had an unusual two years with us. He and I will both be disappointed that he's not done more. He's been blighted with injury and never got a run in the side.
"Mark came in late in the season. On another day or another year, he'd have been a very good player to have in the squad going into next year."