Wednesday have until 31 August to sign players, whether it be permanent or on loan deals and then again in January.
The club can only get loan players in between the windows for exceptional circumstances, for example when a goalkeeper gets a long-term injury.
As a result, The Owls will have to recruit a much bigger squad than the one which gained promotion, despite the fact that last year Graeme Lee, Adam Proudlock, Lewis McMahon, Lee Peacock, Steve MacLean, Paul Smith and Matt Hamshaw missed lengthy spells because of injury.
The Owls boss went into the loan market to get such players as Joey O'Brien, Alex Bruce, Kenwyne Jones, Adam Green and Paul Gallacher as a result - although from next season he will not be as free in the transfer market.
Sturrock told The Star: "The windows mean that managers have kept bigger squads than they envisaged.
"Normally, they would have taken two or three more off their wage bills, and those who have been released have maybe been lesser players."