Banished Cooper returns to Aust swim team

Sensationally sent home from the Commonwealth Games camp, star backstroker Isaac Cooper has made a low-key return to the Australian team at the world short course swimming championships in Melbourne.

The 18-year-old was banished from the team for the Birmingham Games in July for misusing prescription medication.

Soon after Cooper claimed he didn't take a banned substance, with mental health challenges contributing to the decision by officials to send him home.

Finishing second in his heat behind Swiss Thierry Bollin on the opening day of racing, the Queenslander didn't want to elaborate on the details behind his dismissal.

He said he was devastated at being sent home and missing the Games but felt back "in the zone".

"Of course I was disappointed - I'm a swimmer and I'm there to compete and I couldn't, so it was devastating having to watch them, but I'm back now," Cooper told reporters.

"It was a shame having to watch my teammates on the TV but it's great to now be side by side racing against them. 

"Swimming Australia has given me psychiatrists and psychologists who have been really helpful and they've all said that leading into this comp everything's fine - no issues at all - and I'm just in the zone that I've always wanted to be in." 

Finishing Australia's top-ranked swimmer in the 100m at the Tokyo Olympics when 13th, the Queenslander is touted as the new face of Australian men's backstroke.

He was considered a real chance of a podium finish in Birmingham, where the Dolphins won 65 medals including 25 gold.

Cooper said he felt nervous jumping back into international competition.

His time of 50.16 seconds - the sixth-fastest of the morning - eclipsed his national championship mark of 51.42, set in August.

"It's good to be racing; I was pretty nervous leading up to it all day so I'm glad I was able to race well," Cooper said.

"There's plenty of room for improvement in that race too."

Meanwhile, world record holder and defending champion Li Bingjie missed the women's 400m freestyle heats.

According to "Chinese Swimming News and Results" on Twitter, Li came down with a high fever after arriving in Melbourne and still hoped to race later in the week.

Li broke Ariarne Titmus's world mark in October, with the Australian superstar not competing in Melbourne.