Selwood has played 149 games and won three premierships since being selected by the Cats with pick seven in the 2006 NAB AFL Draft.
Simpson was recruited by Geelong just one year later, yet he has played only eight games in his five and a half seasons at the Cattery.
But the 206cm giant from Barnawatha in north-east Victoria is finally making a name for himself.
Two months out from the finals, Simpson has not only managed to fight his way into the team, he has been among Geelong's best players in its recent victories over Fremantle and Hawthorn.
And Selwood is delighted with his progress.
"Obviously they take a little bit longer to come on, the ruckmen, and 'Dawse' is an extra-tall ruckman, so we knew he was going to take a while," the Cats' skipper told AFL.com.au
"He was pretty raw when he came in. He didn't know the game that well, but he had height on his side and he had nice touch.
"So he's had to work really hard for his spot, and that's the way that it should be. That's that way we've always made it down at Geelong.
"You have to earn your spot; you don't just get given a spot.
"The reason he's still here is that he hasn't dropped his bundle. He's made sure that he's worked and worked, and now he's starting to see the rewards for it.
"He deserves a pat on the back at the moment, and he might end up in the right spot at the right time of the year."
Simpson was sidelined for much of the pre-season after needing a second operation on his back.
He played his first game for the year in Geelong's VFL team in early May, then won a call-up to the AFL side for the round 13 clash against the Brisbane Lions at the Gabba.
Like most of his teammates, Simpson started well before fading badly in the last quarter as the Cats gave up a 52-point lead.
But he was given another chance against the Dockers a week later and more than held his own, finishing with 13 possessions, six marks and 34 hit-outs. That night Simpson even managed to boot his first goal at the highest level.
When the 24-year-old lined up against Hawthorn last weekend, he notched three AFL appearances in a season for the first time.
He was an important contributor in the victory over the Hawks, and is expected to stay in the team for the clash against Melbourne at Simonds Stadium on Saturday afternoon.
"Big Dawsey hasn't had too many times before where he's been able to get back to back games, and he's been able to do it this time and perform," Selwood said.
"And we want him to go and do it again on the weekend."
For the moment, Simpson is keeping 2011 premiership ruckman Trent West out of the team. And things are going to become even more challenging for Geelong's group of big men if Nathan Vardy and Hamish McIntosh are able to shake off their injury problems.
"It's great to have numbers to choose from," Selwood said. "I think we'll see Trent West also come back into the side in the next couple of weeks and make his claim.
"It's great just to see the boys under pressure and performing."
Adam McNicol covers Geelong news for AFL.com.au. Follow him on Twitter at @AFL_AdamMcNicol
