Carano, who has no previous acting experience, will play a troubled girl from the other side of the tracks who is given a chance to use her fighting skills for good, reports Variety.
Soderbergh will shoot the movie in January on location in the US, Ireland and Turkey. The director plans to make a globetrotting espionage adventure in the vein of the James Bond films.
Lem Dobbs, who wrote Kafka and The Limey for Soderbergh, penned the script for Knockout.
Soderbergh's next film The Informant! opens next week in the US and on November 20 in the UK.