Alex Gilbey, Baily Cargill and Rhys Healey will have to be patient and wait for the right time to play a part in first team action again.
Both Cargill and Gilbey missed the end of the season through injury, while Healey has missed several weeks of pre-season training while negotiations with Dons were being carried out.
None of the three have played in the first two pre-season friendlies, while Brennan Dickenson has missed out through injury, while Jordan Moore-Taylor is several months away from a return to training.
Tisdale said while Gilbey, Cargill and Healey are back involved in training, they are not going to be rushed back.
He said: "Alex has already participated in training, we've got to hold him back though. You have to be really careful when they come back from an operation that they're not rushed back. He's eager, athletic and fit so we have to be careful. He's behind everyone else, but we don't want to bring him back too early, but he'll be in the thick of it in three or four weeks.
"Baily is the same, he will be in contention for mid-August. And with Rhys joining too, it's like the cavalry arriving. Rhys is a few weeks behind everyone else, but he will be catching up."