While City are fully aware of Hargreaves' injury-hell, Platt believes the midfielder is top quality and worth having in the squad as he bids to get back to his best.
Platt told the Manchester Evening News: "We needed a central midfield player but unfortunately in terms of players going out and bringing in transfer fees, a lot have gone out on loan, so fees haven't come in for them.
"For a few weeks we have understood, from a business perspective, that after signing Samir Nasri, there wasn't going to be a big-name signing coming in.
"You have to get creative. The owners and the board have been terrific in saying 'We know you need a midfield player but we have to be creative about it'."
Platt added: "A lot of people would say it's a gamble, but I think gamble is too strong a word. When you put all the things into the mix it's a calculated risk, and one that we feel is well worth taking.
"What we do know is that if we look at the glass as half full, and it works out for us and for Owen, we get the kind of player that it's very difficult to find - a player that has got that Champions League experience.
"If we are talking about Owen Hargreaves as was, he is one of the best midfield players in the world."