I think it's a vicious circle. A team gets two or three injuries and picks up some poor results. The injured players come back too early and aren't at their best get injured again. More poor results. The back-up players are playing more than they're used to and start to pick up injuries. More poor results. Players start second-guessing themselves, morale goes down and some of the players start to use injuries as an excuse. More poor results. And so it goes.
Conversely, no significant injuries and decent results at the start of the season means that players' morale goes up. Winning makes it much easier to play through the minor aches and pains because all players have a certain amount of pain at all times. Back-ups can step in when required and are coming into a team full of confidence and get boosted by that. More good results. A virtuous circle.
Last season, I reckon Carrick ran his 1st 11 into the ground and we couldn't cope when the season caught up with them. That's the downside of not needing to change a team. Last season we had 11 players who played 2,000 minutes (6 played 3,000) or more in the Championship plus Archer who would have easily done so in a full season. This season we're on track for around 7 to have played more than 2,000 minutes and probably only Howson and Dieng to manage 3,000. On the plus side, none of our players look tired at the moment. Towards the end of last season, it felt like a lot of our players were struggling to maintain their levels.