An alleged coward-punch attack which left a hulking basketball star with bleeding on the brain was not unprovoked, a court has heard.

Brisbane Bullets centre Harry Froling, 24, was assaulted after leaving a nightclub at Illawarra, on the NSW south coast, around 2am on Sunday.

CCTV footage showed the 210cm, 123kg athlete punched in the face on Crown St.

Froling was allegedly assaulted by Nathan Mesinez, 19, who was charged with affray and inflicting grievous bodily harm after he handed himself into Wollongong Police Station on Tuesday.

In successfully applying for bail, Mesinez' lawyer Caitlin Drabble told the Wollongong Local Court her client felt 'harassed' by the NBL star, who earlier was asked to leave a nearby nightclub after 'showing signs of intoxication.'

Froling earlier was a key figure on court when the Brisbane Bullets beat the Illawarra Hawks 103-86.

After he was allegedly assaulted by Mesinez, an apprentice carpenter, Froling was taken to Wollongong Hospital at 2.40am.

He refused to have a head CT scan, before staff went to check on him again.

They then discovered Froling had ripped out his IV drip and discharged himself.

Froling then returned to Queensland with teammates, but complained of headaches and was taken to Brisbane's Prince Charles Hospital, where doctors found the serious head injuries and rushed him into surgery.

He won't play again this NBL season.

Townsville raised Froling made his NBL debut in 2015, and the powerful centre also had a successful college career in America.

His brother Sam is also an NBL star, and sisters Alicia and Keely both play in the WNBL.

The family as famous as they come in Aussie basketball, with father Shane playing 271 career NBL games, while mother Jenny is a four-time WNBL champion.