Blackpool chairman Karl Oyston has insisted he is up to the job after being criticised by boss Jose Riga.
Spurs boss Mauricio Pochettino says Roberto Soldado and Andros Townsend will not be sold during the transfer window.
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.