Just because there might be a bit of hype about you after a couple of games for the first team it doesn't mean you've made it," he told ManUtd.com. "You've almost got to work even harder when that happens to prove that you can stay in there.
"And having Rio [Ferdinand] next to me in the defence was brilliant. He never stopped talking to me and helped me so much with my positioning and marking."
Simpson knows he faces a tough task in trying to gain a regular run in the side, but believes this season's influx of new players has really benefited the team.
"The addition of the new players in the summer has meant there is a good group of young lads at the club now and it makes training really good fun and exciting," he said.
"There's good competition for places because everyone is working hard to get their chance. That can only help the team."