Brisbane Broncos Training Session
Tesi Niu leads a shrinking list of fullback targets for the Newcastle Knights. (Photo by Bradley Kanaris/Getty Images)

Broncos fullback Tesi Niu is facing a battle to play Round 1 after limping from the Red Hill training track on Thursday morning with a suspected hamstring injury.

As first reported by Nine News, captured footage shows the 20-year-old stopping short after hitting the line in a drill.

Although Brisbane are yet to confirm the minutia of the Tongan international's injury, early reports suggest Niu could be set for a five-week stint on the sidelines.

The Broncos have announced that David Mead will replace Niu at the back for this Saturday's trail clash against the Titans at CBus Super Stadium.

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After debuting in 2020, the Queenslander laced the boots on 16 occasions and dotted down for eight tries, including braces against Cronulla in Rounds 16 and 24.

Should Niu spend the next five weeks rehabilitating, he will miss both of the club's pre-season clashes.

However, if his preparations run smoothly, a place within Kevin Walters' lineup to face South Sydney on March 10 at Suncorp Stadium.