With the cut-off point looming at the end of the month, any purchases or loans to replace long term injuries will have to be put on hold until the new year - half a season away.
"It is going to be a new experience, obviously the same for all teams," says Simon, "but it brings into play timing of injuries.
"You can never tell when things are going to happen, therefore it is vital to keep players fit, and running up to that deadline you want to be injury free.
"But it could play a major role in how teams do this year and it is going to be a difficult situation for all teams, especially if you haven't got a strength in depth squad like Manchester United.
"They are able to replace their players fairly easily, so time will tell on that one."
Simon is relatively pleased with the injury situation two weeks until the start of the new season, and says: "We haven't been too bad so far, touch wood, though we have had a couple of little niggles that pre-season always throws up.
"Don Hutchison is our only long term one.
"Paolo is progressing very well. It is a case of just nurturing him through and we push him on again after his first gentle session of football, which he has had.
"It is one of the small muscles in his foot that has been the problem, but he has been rehabbing all summer in Italy. He has worked very hard and has come back very fit.
"It was a minor setback for him, but it should be fine for him to get back to speed.
"Steve Lomas' knee has settled down and we can hopefully ease him back to training after the weekend.
"Steve Bywater's possibly got to have an operation on a fractured scaphoid, which is a bit of a blow for him as he had a similar injury last year.
"This is a new fracture in the same bone and he needs to see a specialist early next week, who will decide when he needs to get it operated on.
"Shaun Byrne is back after coming through a full scale practice match unscathed on Wednesday, and will be in action against Dagenham tonight.
"Youssef Sofiane played in the practice game as well and is doing fine."