Williams left United last summer for Shrewsbury.
“I’ve not spoken to him for a couple of weeks because he’s a bit down with his back injury at the moment.
On leaving United, he added: “It was my decision, no one else’s. I had six months on my contract and spoke to Nicky Butt, head of first-team development.
“I told him, ‘I believe I’ve enough talent to get to where I want but it’s unrealistic to think I’m going to break into the United team having just turned 20.’
“It gets to the point where you think, ‘I want to be a footballer, I want to play at the highest level I can and there’s no point wasting my time in the Under-23s.'”