Their contracts were due to expire on Tuesday but head coach Gerhard Struber had indicated that both would stay for the final nine games of the season.
The 27-year-olds were both on the bench for Saturday’s win at Queens Park Rangers, with Dougall coming on. They have been both named as released players on the 'retained list' the Reds announced this afternoon.
Radlinger has played 18 games since arriving last summer while Australian Dougall – whose option of a further year on his deal has not been taken by the club – has made 43 appearances in two years at Oakwell.
Left-back Dani Pinillos and winger Mamadou Thiam have also left the club.