The 24-year old USA international midfielder underwent a medical and agreed personal terms with the Roman outfit last week but Chievo sporting director Giovanni Sartori says the deal is not yet finalised.
"With the Giallorossi there is a negotiation in process, it began well but is not yet complete," Sartori told Tele Radio Stereo.
"We need to define the details and believe that there is good will to define them. I want to reiterate that these are details and not problems.
"Bradley is a great player, he can play in three roles, central midfield and on either side of a midfield three, capable with either foot on the ball.
"For him, we received many offers, but Michael has shown preference towards Roma. Chievo is obviously a minor club compared to Roma, but thanks to him we too have achieved some significant visibility in America.
"His name is known in the United States, his father was the Coach of the national team.
"Bradley brings technical advantages, but also aspects of vision that in Rome could possibly be exploited very well.
"For now he is training with Chievo, but it is clear - he wants Roma and we will try to please him, for an agreement that would also suit us."