Anil Sharma (42), who had represented India at the paralympic games at Rio in 2016, was allegedly beaten up by seven people, including the accused, on July 21, police said.
Ashwini Naath alias Aashu (34) was arrested near north Delhi's Subzi Mandi police station, said Mandeep Singh Randhawa, Deputy Commissioner of Police (Central).
The other accused are on the run, he said.
Aashu told police he and other accused had a heated argument with the player over some issue which led to the attack, the police said.