Umaga, 33, told The Dominion Post: "This will be my last year playing professional rugby, but there's a good Petone President's side that plays these days.
"I know a few of those guys and I'm getting to that age. There are things in the pipeline that I won't mention now. I'll keep my eye on them and we'll see how things go."
The centre ruled out a return to the game as a coach in later years.
"I couldn't coach at this level," he said. "You never say never but because I've played at this level for so long I'd be one of those coaches who thinks he should still be playing.
"If they weren't doing it properly I'd be out there trying to show them. You don't want that as a coach. You lose respect like that."