If that was true, then resting tired players during a 2 week international break might help.
However, it doesn't take a Beautiful Mind to see the pattern of how many players we've injured during international breaks, winter breaks and pre-season these past few years to see it's an issue.
Also, playing 8 games over 13 weeks at the start of season should be quite manageable even for a 34 year old.
However, if players like McGinn and Miller are at risk, then we should be rotating them sooner, not crocking them in training sessions.