Actually he just has nothing to say. It can happen with lack of scouting (though even with that it should be easy enough to say "weaker foot), or a tactically-weak assman, or maybe even an opponent that doesn't need any special instructions (though can't say I've ever seen that, sometimes all they say is "weaker foot", but what if every guy on opponent's team is dual-footed).
But anyway, you'll see it in lower leagues when you have a poor staff.