Doncaster have signed Sheffield United defender Andy Butler for an undisclosed fee on a two-and-a-half-year deal.
The 31-year-old joined Rovers on loan in October and has since made 13 appearances for Paul Dickov's side.
Butler told the club website: "I'm really enjoying my time here and the manager's brilliant with me."
Meanwhile, fellow defender Luke McCullough has signed a new two-and-a-half-year deal.
The 20-year-old joined Rovers from Manchester United in July 2013 and has made 43 appearances for the club.