Praise be to Allaah.
Al-Rasheed is not one of the Names of Allaah, because it was not narrated either in the Quraan or in the Saheeh Sunnah. The Names of Allaah are as they were narrated (with no room for ijtihaad). It is not permissible to call Allaah by any names other than those by which He called Himself or He was called by His Messenger (peace and blessings of Allaah be upon him).
And Allaah knows best.
Sheikh Muhammed Salih Al-Munajjid