I was thinking the other day of various Northern and Bulls greats who were still doing a good job, had more to offer but called it quits, for reasons other than injury. Off the top of my head there was:

Marcus Bai - Was aging but still quality. I think he signed on for another year then changed his mind.
Karl Fairbank - Retired prematurely imo probably because Super League had just started and being full-time and a farmer isn't compatible. I'd have liked to see him as a full-timer even at 33.
Joe Vagana - Still a monster even in his final year. Broke his arm in 2008 and retired that year aged about 32. Could have still done a job
Christian Richardson - played once for Hunslet Academy and then lost to the game. Absolute talent. Became a moderator.

Who else?

Steve Mcbanana and James Lowes should have never retired from playing irrespective of their age and performance.

Stanley Gene had at least another decade left in him.

Think a few aussies could have kept on going for another season if they weren't far from home. Graeme Bradley, Brad Mackay, ...

What ever happened to Jon Scales?

One springs to mind.

Didn’t Bryn Hargreaves retire from the game fairly young about 27 or so? Although I think he was very unhappy with the state of the game at the time and landed a decent job outside of the game. At least the bulls showed him how stable a rugby league career could have been oh wait....

Didnt Lauaki retire early but just forgot to tell us all.

Sadly we've had a few like that mate. Ran on the pitch and then acted entirely retired for 80 minutes.

If only... Lauaki could barely last ten minutes before blowing out of his ass!

One who drifted away whilst I think still had a lot of potential was Dave Halley

Went playing Union with his mate Kern Yates at Broughton Park I think. Saw him playing years back at Leo's 7's in Leeds. Glad I didn't play him

I think sir Keith Mumby had a couple more years left. Tackled round the legs

Seeing the name, 'Le Penguin' reminds of another Bulls' great who left the team a little early. Mind, that was due to a certain referee who allegedly repaid a few grudges by sending him off* when we were in the driving seat at Saints in the play-off a game we sere definitely going to win. So Hail Graeme Bradley, who could easily have done an extra fifty minutes of that match and probably another play-off game.

*I base my claims on the fact he was found not guilty by the RFL committee.