The England Under-21 international made a surprise switch to the Etihad Stadium last weekend in a £12million deal which could rise with add-ons.
Rodwell, who had come through the Toffees' ranks having joined the club as a seven-year-old and only signed a new contract in May last year, was seen as a player who could develop into a major star at both Premier League and international level.
However, his development did not progress as quickly as had been anticipated in the last 12 months and he was not helped by a hamstring injury on duty with the senior England team which restricted him to just five appearances from mid-November.
Moyes appears to have decided he could improve his options with the money - of which a significant proportion he will receive to re-invest in players - he could get from selling Rodwell.
"I had known about it for a while and I thought it was something that was right for Jack and right for Everton," said the Toffees boss.
"It was something which I felt at this moment in time was right.
"It gave Jack an opportunity to go to a really good club and take his chances there.
"It gives us a chance to do a little bit more business in the transfer market having raised the money.
"Hopefully I will try to add to the squad before the season starts."
Moyes insisted he was not compelled to offload Rodwell as the books had already been balanced by the sales of other players but removing the player's £40,000-a-week salary from the wage bill has given the manager further room for manoeuvre.
"Last year we had to do it (sell), this year we didn't have to do it as we had already sold Tim Cahill (to New York Red Bulls) and Joseph Yobo (Fenerbahce)," he added.
"It wasn't a necessity to do it this year but I felt it was the right thing and gave us a chance to have a look around to see what we could do.
"We are out there actively trying to bring in another couple of players at least."
He may have lost Rodwell but, perhaps more significantly for Moyes, he was able to bring Steven Pienaar back to the club after a disappointing spell at Tottenham.
The South Africa midfielder spent the second half of last season on loan at Goodison Park and made an immediate impact and was the one deal the Everton boss knew he had to complete.
"The Pienaar deal was needed for everyone. The supporters needed it and certainly the players and the staff needed it," said the Scot.
"His performances last season were terrific. I couldn't turn around and say it was the best-ever financial deal or signing we have made.
"His age (30) goes against him and we had to buy him back for more than we sold him but I think for everyone he was a key part to how we finished the season and did so well.
"I think everyone would agree it was imperative we got him back.
"I don't think you'll ever see Steven as a regular goalscorer, he supplies and makes goals and helps our team produce goals but it was good he did score two or three last year and hopefully we would get more of the same."