McIntosh and Simpson have not played in the same side since the Cats were flogged by 110 points by the Sydney Swans in round 11, but have regularly swapped No.1 ruck duties since.
The athletic Mark Blicavs has been preferred as back-up by coach Chris Scott, leaving McIntosh and Simpson in healthy competition to stake their claim.
"It does (motivate me),” McIntosh said after the Cats’ big win over Melbourne. “Dawson and I had a really good relationship and partnership the first nine or 10 weeks and it worked really well. Since then (we've) been in and out of the side.
"If it's one of us or both of us each week, if it's myself and 'Blics', I'll do what I'm told from 'Scotty' and we'll go from there.
"But I'm looking forward to reuniting my partnership with 'Daws' - if that happens in the next few weeks - and I feel like I can be a real positive strength for the side."
McIntosh carried most of the ruck load against the Demons at the MCG on Saturday.
The 203cm former Kangaroo tallied a season-high 20 disposals, took five marks, won 26 hit-outs and booted a goal on the run from 40m just before half-time.
He easily outpointed Mark Jamar, who had 24 hit-outs but only six disposals.
"You love going into the game knowing the responsibility is on you. It was a real one-on-one match up on Jamar," McIntosh said.
"(If) next week I get the chance to do it again I'll be lapping it up and hopefully play a good game."
McIntosh was plagued by injuries last season and didn't play a game at any level, but has built confidence in his body in 14 matches this year.
"I feel really good. Don't get me wrong, I feel 29, sometimes I do feel old. But it's been coming up really well," he said.
"Getting out on the training track once or twice a week is just so important for me to get a lot of confidence in my body and it helps with my form.
"I felt like I started the season pretty well, but then the last few weeks have been a little bit inconsistent – probably like the side."
Chris Scott, who said it's likely the Cats will play two ruckmen again this season, was pleased with McIntosh's work around the ground against Melbourne.
"The best part for us and for Hamish is that he's marking the ball in general play. It's nice to have a dominant ruckman at the stoppages, but when they mark it around the ground that really helps," he said.
"He's not the best mover in the competition, but he's smart and he gets the ball and he uses it pretty well.
"I thought that was a pretty good performance today and, at least the numbers say, he dominated the hit-outs as well."