Jalal Uddin was found injured in a play area near the Jalalia JaamÃ© Mosque on 18 February. He died later in hospital.
The 21-year-old is the third man to be arrested over the 64-year-old's death.
Mohammed Hussain Syeedy, also 21, of Ramsay Street, Rochdale, has been charged with murder and conspiracy to commit murder.
A 17-year-old previously arrested on suspicion of murder is on bail until 20 April.
It is understood Mr Uddin was a qari, or Koran reader, at the Jalalia JaamÃ© Mosque. He is believed to have been on his way home from a friend's house when he was assaulted.
Mr Uddin died from a head injury, a post-mortem examination found.
Police are appealing for any witnesses who were in the South Street area at the time of the attack to contact them.
Anyone with information is urged to contact police or Crimestoppers.
A man has been arrested on suspicion of conspiracy to commit murder after a prominent member of a mosque in Rochdale died from a head injury.