Thorne finished as top scorer at Valley Parade for the last two seasons but has seen his time at the club disrupted by a series of injuries.
The League Two side are now expected to sign 20-year-old Hull City striker Ryan Kendall on a one-month loan deal.
Thorne's departure follows that of Michael and Rory Boulding who left the club by mutual consent on Monday.
If Peter [Thorne] wants to come here and help with my coaching, I've offered him that chance
Bradford manager Peter Taylor
Bradford manager Peter Taylor told the Telegraph & Argus: "It was very hard for me to speak to them. I still don't know exactly what's happening next season.
"But I said that if I am here, I didn't think I would be offering them another contract.
"Their response was terrific. They were both so respectful and totally understanding."
Thorne was one of former manager Stuart McCall's first captures when he arrived in July 2007.
After signing a new contract for the following season, Thorne missed much of the campaign with persistent neck and shoulder problems.
Why let players go now? Surely this means PT is staying next season?
scottishcityfan
He considered retirement towards the end of the campaign but signed a further one-year deal for the 2009-2010 season.
However, he started only three matches this season as injuries continued to hamper his time at the club.
Taylor said: "It's a bit different with Peter. Michael has had a frustrating time with the club while Peter has been an absolute legend here.
"If Peter wants to come here and help with my coaching, I've offered him that chance."
Taylor also confirmed they were hopeful of bringing Kendall to Valley Parade on a month-long loan.
"Ryan is full of energy and will run all over the place. He puts defenders under pressure."
Source: BBC Sport
Source: BBC Sport