Jones, 23, has spent much of the last two seasons sidelined by injuries, including a torn hamstring and recurring back problem.
He was released by Wrexham following their relegation to the Blue Square Premier.
Ferguson is confident he will be fit to move to London Road before the start of the new season: "He's a had back problem but it's more a lack of flexibility in that area and we can sort that out with simple stretching.
"He's had a scan and there's no serious problem.
"It's a process we've got to go through with players nowadays and he'll be getting (a medical) and I'm sure everything will be fine."
The Posh manager also confirmed he is still confident of signing at least one of two players at Premier League clubs on loan but admitted a deal was unlikely to be finalised soon.
Ferguson added: "One wants to go back and have pre-season with his club, which is fair enough, and the other may make his mind up soon.
"But I'm prepared to wait as they're two quality players."
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.
Bookmark with:
What are these?