Preston North End assistant manager Glynn Snodin thinks disruption to the defence was a major factor in the poor run at the end of the season.
They took just one point from the last six games and had to settle for an 11th-place finish after at one stage they were challenging for the play-offs.
Reflecting on the slide in form during April, Snodin said: “When you look at the season, we recovered from a bad start and went on a great run.
“Those last few games were disappointing but we had a lot of our defenders missing at one time or other.
“When you look at all good and successful teams they have a solid defence, the selection is consistent.
“You can change your wide players and strikers but you need that same group of lads at the back. They are a unit, they have a good understanding.
“We had the injuries to Tom Clarke, Greg Cunningham and Tyias Browning, while Alex Baptiste was suspended for three games.
“At the end we were almost having to change things every game.”