Jeffries, 32, is going home to work in mining, where he will combine his job with playing for Kurri Kurri Bulldogs in the regional New South Wales league.
He said: “Coal mining is a massive industry in Australia.
“People are queuing up to get into that line of work so I’m grateful to have landed this job.
“It’s a no-brainer really. I don’t know what my exact role will be just yet but I’ll be working in the mining industry.
“I know that when I get there I can diverse into certain categories of mining – I can be open-cut or underground.”
Jeffries has played in Super League for 10 years, with two spells at both Wakefield and Bradford, making 236 appearances.
He becomes the second Bulls player to confirm their exit from the club, following on from Tom Burgess‘ decision to sign for South Sydney Rabbitohs, while 17 other players are out of contract this winter.