Brisbane NRL recruit Jack Bird admits he might need to "slim down" a little bit but says he couldn't care less about supporters sledging him as overweight.

The utility made his long-awaited Broncos debut in their win over the Wests Tigers, having undergone shoulder surgery that delayed his start to the year.

Brought north from Cronulla on a multi-million dollar deal, Bird admitted during pre-season he had a "bit of a gut" after a television station aired pictures of him without a shirt.

Social media again lit up with criticism of the 23-year-old's body shape on Friday night during the 9-7 victory over the Tigers.

Not that he's taking any notice of it.

"I don't really care what they think, to be honest," Bird said on Monday.

"I'm happy with my weight, I feel good.

"I do have to lose some body fat but it comes with time. Being injured doesn't help.

"Give me time and hopefully I can slim down a little bit but I'm feeling healthy."

Bird has never been particularly ripped but it hasn't stopped him in the past, having represented NSW in State of Origin five times, as well as winning the 2016 grand final with the Sharks.

"I've got pin legs," he said.

"I do weights every day and they're still pin legs.

"I'm not very strong in the gym, I don't lift heavy.

"I just go out there and try and use my strength when I run the ball."

Bird said his shoulder pulled up well from his first match since September but was nursing a sore sternum, a recurring injury that caused problems last year and over the summer.

He said he had a "weak spot" he would likely have to carry for the rest of his NRL career.

"It's just how to manage that and I've got to be careful, but you can't be careful in a rugby league game, can you?" he said.

Despite his versatility, Bird is expecting to be deployed at left centre for the rest of the season.

"I haven't had any talks to Wayne or anyone else at the club with positions, beside centre. So I guess I'll be centre all year and I'm happy to do it," he said.