The ERL is a joint venture between the Rugby Football Union (RFU) and Premier Rugby Limited (PRL), set up in 2001 to administer and manage elite professional rugby in England.
Baron, who remains in his role as chief executive of the RFU, is widely respected for his role in bringing the two sides together following years of in-fighting after the game turned professional in 1995.
Baron tendered his resignation at an ERL board meeting on November 4, effective November 11, and the board has asked the RFU to nominate a suitable replacement.
