A Brighton and Hove Albion player, in his early 20s, was arrested Wednesday morning with a second man in his 40s.
The club later confirmed that the player was involved in the investigation.
An unnamed footballer for legal reasons has been reported to have been escorted by a police officer from Brighton Beach Arch Night Club.
A Sussex police spokesman said: “Two men have been arrested after reports of a woman being sexually assaulted at a Brighton location early Wednesday morning.
“A 40-year-old man from Brighton and a 20-year-old man have been arrested on suspicion of sexual assault and remain in police custody at this time.”
The woman is receiving expert support from authorities, a spokeswoman said.
Brighton and Hove Albion FC said it was helping police with the investigation, “The matter is subject to legal proceedings and therefore the club cannot provide much response at this time.”