The easy answer to the question...
Who do you jettison to create room to put Peterson back on the 40-Man?
Keep Rio and let him have the ABs you don't give Camargo at 3B. Send Adams down and keep Santana and DPete as OFs 4/5 until Acuna comes back up - Santana can be the backup CF until then and you can platoon Peterson and Tucker in LF to provide some pop. Cut Santana loose when the Manchild's clock starts.