"Liberty have not got far enough down the road to make any commitments yet," the 61-year-old Briton, who left the sport at the end of 2013 after decades of involvement, told the BBC on Wednesday.
"I'm doing a little consulting to help them better understand F1 but that's all."
Germany's Auto Bild had reported this week that Brawn, a former Ferrari technical director who won titles with Michael Schumacher and also with his Brawn GP team in 2009, had agreed a role with Liberty.
Other media reports indicated he was set to work as a sporting director, including liaising between the teams and governing body and assisting with plans for the future.
Bernie Ecclestone remains at the helm of Formula One and Brawn said any future role on his part "all depends" on what the 86-year-old Briton decides to do following the Liberty takeover.
