Whenever you get lots of injuries, particularly if they are muscle and tendon (which seem to be the majority of our issues), you have to question the quality of the warm up and warm down techniques used.
On top of that you have to query the level of fitness training completed in the summer.
We all know summer fitness work was a serious weakness under MoN (hence the shit March every season) and that caused Houllier a lot of issues last season, he tried to push the fitness levels up during the season which caused massive injury issues in October and November.
Can't really see any reason for it this season though, McLeish was in before pre-season so he should have been in full control of the fitness training.