Simpson, 33, said the decision whether his playing career extended into a 16th year rested with the Kangaroos, after he declared himself mentally and physically fit to go around again.
Simpson said a farewell game was not a priority for him but he was prepared to be told of the club's intentions before round 22.
That could see the former club captain end his long career at AAMI Stadium against Port Adelaide in the Roos' last game of the home-and-away fixture.
"I'll know before the end of the season," Simpson told afl.com.au, ahead of the club's round 15 clash with Hawthorn.
"It's hard to end on a good note, an AFL career. Not many people do. The end is always a bit sour. I'll weigh that up as well.
"I just want to enjoy the last eight weeks."
As far as making that decision, Simpson said he really didn't know how the club – or himself – would feel as the season drew to a close.
"I honestly don't know. When you get to my age, you have a bad game and you start to think, 'The game has passed me by'," he said.
"Then you have a good game and you think, 'Nah, I'm going alright here'.
"It just depends on the week. If you ask me next week and I've played poorly, I'll be down in the dumps.
"I don't know where the club is heading and what they want from players like me.
"They might want to go with youth and rebuild, and realise there's no point in having a 34-year-old playing if they're not thereabouts next year.
"It will be a group decision, that one."
Simpson remains adamant he won't end up a player that is selected purely on past heroics. He also refuses to take up a spot on the club's list ahead of a budding star.
While he felt he was still making an impact, he understood there were more factors to be considered when making the ultimate decision.
"I keep looking at players like a Jeff White, who was 31, 32, and it just ended because the team was heading in a different direction," he said.
"I don't know whether we're going to be like that or not. I don't know if we need a bit of stability and leadership around the place, because we've got some pretty good leaders.
"I don't want to be holding back a Jack Ziebell. I don't want to put the coaches in a position where they say, 'We don't want to play Simmo this week but we can't drop him because he's been around for awhile'.
"Those thoughts have been running through my mind.
"Physically I'm okay. I love footy, so mentally, I'm fine too.
"Robert Harvey at St Kilda, four years in a row they were thereabouts and needed a top-up player, a bit of experience, so he had a really good position in the side.
"We're in a different position so I'll have to wait and see."
Simpson said he wanted to enjoy the final eight rounds of the year without thinking about whether or not he would be at Arden Street in 2010.
"I want to win some games, and for me, I just want to enjoy the footy club atmosphere," he said.
"I enjoy coming here every day and seeing another wall getting put up in the redevelopment.
"We're going to be a different club next year, with a new coach, whether it's Darren or someone different.
"I just want to enjoy it and back in the coach, and I don't think we're that far away from winning some games."
