The likes of Mark Yeates, Jason Kennedy and Raffaele De Vita have all had to be patient as Parkinson has relied on the same group of players who won promotion in May and embarked on last season's Capital One Cup run all the way to Wembley.
A settled side has been key to the Bantams' climb up to fourth in the table on the back of one defeat in their opening nine league games, with leading goalscorer Nahki Wells (ankle) the first to miss out through injury in last weekend's win at Walsall.
"Without a doubt that continuity has been crucial," Parkinson told Press Association Sport.
"In my mind, right back in pre-season, even though we brought five or six players in, I felt I wanted to go with the team which got us over the finish line at Wembley.
"We've managed to do that, but just recently we've had some disruption for the first time through injury, but we've now got players I'm very confident can come in and make a contribution and we will definitely need all of them."
Bradford, unbeaten at home this season, take on Tranmere at Valley Parade on Sunday and Parkinson added: "We keep reminding the lads that we've got to make it difficult for the opposition on our home patch.
"You can't guarantee a win every other week, but what we can guarantee is that the opposition are sat in their dressing room afterwards and think that was a really tough game."