"AFL is a pretty scary game," he said. "Every week you think you can be only two weeks away from playing reserves.
"You never think too far ahead. It (100 games) is something I thought about only last week and this week that I could actually get there.
"I suppose looking back, playing my first game, I didn't actually think I would make my debut, let alone play 25, 50 and 100 games.
"When you think about it, it's a lot of games and hopefully I have a lot more to go in my career."
Mop-haired McGregor, 24 and an imposing 195 centimetres and 95 kilograms, is one of the best examples of a late-choice draft pick being able to forge a successful AFL career.
He made his AFL debut in 1999 after being Adelaide's seventh pick (No. 75 overall, and from SANFL club Woodville-West Torrens) in the 1998 national draft after the Crows had already taken Brett Burton (16), Tyson Stenglein (29), David Gallagher (32), Bryan Beinke (34), Lucas Herbert (48) and Clint Kirey (63).
"I suppose the main thing you want to look at in your football life is to be part of a successful side," McGregor said. "I think we are going in the right direction and it will be great if I can be part of an emerging backline.
"Gary Ayres showed a lot of faith in me the past two years and gave me the chance to play, and hopefully I can reward that to the Adelaide Football Club for what they have done for me."
McGregor, who said he thought his style of play was better suited to centre half-back than centre half-forward, described Friday night's clash with the Demons as 'a massive game'.
"They're in the top four and one of the premiership favourites, so it's going to be a big game," he said.
"I think it (a win) would make a big statement that we want to make the eight and we're a good side, and we are going to be hard to beat during the year.
"If we can knock off a side like Melbourne after just getting over the top of the Kangaroos, who are also in the top four … I think they are the kind of teams we want to beat. You have to play good footy to beat them and that shows the other teams we are going to be around the mark.
"We rate ourselves and that's all that matters to us. We know where we want to go and we have had a lot of confidence in ourselves since pre-season. We know we are a good side and we want to continue to be like that."
