The attack is thought to have happened somewhere between the Corn Exchange and the Cosmopolitan Hotel in Lower Briggate at around 3.45am.
A number of road closures were put in place throughout the morning while the scene underwent forensic examination.
Police also issued an appeal for information as they worked to piece together the circumstances of the attack, which remains under investigation.
But a spokesman today confirmed that the victim was now under investigation himself.
He said: "The victim was released from hospital yesterday and taken into custody on suspicion of possessing Class A drugs with intent to supply and possession of an offensive weapon.
"He was later released under investigation."
Anyone with information on the attempted murder is asked to contact Leeds District CID via 101, quoting crime number 13170515555.
Information can also be passed on to independent charity Crimestoppers anonymously on 0800 555 111.