Ipswich boss Mick McCarthy has offered a short-term contract to former West Ham midfielder Jack Collison.
Chairman Fawaz Al Hasawi has vowed to strengthen Nottingham Forest year on year, with loan arrivals possible.
The club say they have paid a "substantial" undisclosed fee for the 27-year-old, who has been on loan with the Millers since October and scored four goals in 16 appearances.
Frecklington has put pen to paper on a two-and-a-half year deal after the two clubs agreed a fee earlier this week.
The transfer is subject to Football League and FA ratification.