Port Vale manager Lee Sinnott has made Manchester United defender Adam Eckersley his first permanent signing at Vale Park.
Eckersley joined the Valiants on loan in October but made just two appearances during his stay.
He was sent off on his debut against Brighton and then had his stay at Vale Park cut short by injury.
He told the club's official website: "They told me before my injury they would like to renew my loan, and obviously with the injury I couldn't come back for six weeks.
"But I believe we have got a good chance of staying up in League One and I am happy to be back, it is a good club with good people here."
He added: "It's a big help knowing most of the players from when I was here before and I also knew one or two them from when I played here in pre-season."