Competition for spots has made players "pull their finger out" at Cronulla training - and maybe help the re-signed Jack Bird put his hand up for NSW Origin duty.

Sharks coach Shane Flanagan has provided no guarantees for NRL Rookie of the Year Bird, saying pre-season form will determine his 2016 backline.

But Flanagan did tip the 20-year-old Bird to crack the Blues Origin team in 2016 if he answered the challenge.

Flanagan said the early signs were good, backing Bird to "go to the next level" after knocking back a lucrative offer from St George Illawarra and re-signing until 2017 this week.