Manchester United's Casemiro blow nothing compared to Sheffield United's 'shocking week'
Captain John Egan, vice-captain Chris Basham – twice – and summer signing Tom Davies have gone under the knife during the international break.
"It was a shocking week for injuries," said Heckingbottom when asked about Egan and Davies, who missed the 3-1 defeat at Fulham. "They are going to be out for a long time.
"John was in the game (at West Ham United last month), he was jumping for a header, Tom it was literally the last kick of the ball in training and he hurt his thigh.
"It's a nightmare. Because we were behind in terms of squad numbers when we started the season, I felt we were just getting to the point where we had made the signings by the end of the window and we were getting there.
"It's sort of put us back to square one a little bit.
"What is hurting us is the length of the injuries, we have still got people out from last season. We can't lose any focus, it's all about getting through these next few months until January when we can do something about it."
Davies was building up his fitness after being released by Everton in the summer. His three appearances have come from the bench.
"He has needed an operation and he is really down," said Heckingbottom. "He was a in a position where he was ready to go.
"Everyone has to step up and fill that void."
Basham is still in hospital after a second operation on the ankle he broke at Craven Cottage. With Egan missing, he could have expected a run in the side.
"He is going crazy inside those four walls," said Heckingbottom. "He has had a couple of operations that were needed, hopefully he will be getting home to his family in the next few days."
The older the player, the more people fret about a serious injury being terminal for their careers. Basham is 35.
"Everyone knows how naturally fit he is," said Heckingbottom. "He is blessed with really good endurance, he will come back fit as a fiddle, that won't take long.
"The surgeons are really happy with the work they have done."
Heckingbottom said George Baldock is "getting closer" after damaging his calf training with Greece in September's international break. Ben Osborn is back in training after the injury he picked up in August, and may be sent out quicker than planned.
"If there is a chance for the bench for the last 15 minutes and it is not going to harm them, we will be using them," explained Heckingbottom.
Saturday's visitors for the 8pm televised kick-off have their injury problems too, but have a deeper squad to deal with it.
Midfielder Casemiro has remained in Brazil for treatment on a "small issue" suffered on international duty.
It was a surprise when the 31-year-old played against Uruguay having come off injured 70 minutes into Saturday's World Cup qualifier against Venezuela.