Rock, 38, was one of four assistant coaches released by the club early last week and said he could see himself making similar decisions in Scott's position.
"You need to be pragmatic about these things," he told afl.com.au.
"The AFL system is a tough environment for any coach and if I was to become a senior coach I would like the idea of being able to assemble my own team of assistants as soon as possible.
"Brad needs and deserves that opportunity and I saw this as a chance to move on. I've left North on great terms and I'm looking forward to my next challenge."
Rock departed Arden Street after 10 months but left with the belief the midfield was in a far stronger position than when it was handed to him.
"In the circumstances I'm quite pleased with how we eventually progressed across the midfield," he said. "There were definite improvements with the group's abilities across planning, communication and their discipline.
"Toward the end their success in working together was excellent and I think we proved that with good wins against St Kilda and then Port Adelaide on the road."
Rock was particularly impressed with Andrew Swallow's output in 2009.
Swallow played all 22 games after just three in 2008 and is a strong chance to win his first club best and fairest award next month.
He said Rock had a lot to do with his re-emergence.
"As far as midfield coaches go, I learnt more from Rocky than anyone else in my time at North," he said.
Chief of football Donald McDonald acknowledged that Rock would be a valuable addition to another club's coaching staff.
"He did a tremendous job with our midfield under trying circumstances," he said.
"Even though it was only 10 months that Rocky was with us, when there's a change of coach there's generally a change in a hell of a lot of areas. He understands that.
"The relationship between Rocky and us is good. He's a premiership player and a life member so the last thing we want to happen is for him to be disillusioned with anything."
Rock added he was confident new assistant coaching opportunities would become available in the coming months.
"My contribution to coaching is very much unfinished business, you are learning all of the time and that definitely applies to me," he said. "I know the areas I can improve on and my passion and work ethic is as strong as ever.
"It's just a matter of finding a good fit and making the most of my next opportunity."
Rock joined the Roos as midfield coach last October after two seasons in that role at St Kilda (2007-08) and two at Melbourne (2005-06).
Three years in charge of TAC Cup side North Ballarat (2002-04) followed his 222-game career with North Melbourne and Hawthorn, which included the Roos' 1996 premiership.
He confirmed he had presented for the senior position at Richmond, which was eventually awarded to Damien Hardwick, and said he had benefitted tremendously from that process.
"I've got the passion, honesty and work ethic to become a senior coach," Rock said. "Until that door's closed, I will never give up."
