Westley said he felt "humiliated" on Saturday after a 3-1 home defeat by lowly Carlisle left them 18th in the table.
He told the club's official website: "Our current squad is a mixture of lads I inherited and lads I have brought in.
"It is a work in progress but some of the work is going to take time to complete because contracts exist.
"I am happy for any contracted player to stay here long term if that is what he wants. But I certainly won't renew contracts with players who deliver poor results."