It's not an excuse, but it has to be hard getting up for a team like the Jaguars especially when you do not control your destiny and are depending on teams like Cleveland and KC to make your game the least bit relevant. Chances are most likely that this game and next week's game are completely meaningless.
I don't buy the whole 'momentum' thing. Sure in some cases playing like crap or resting on the last week(s) has hurt teams, but I've seen plenty of teams go into the playoffs on fire only to be one and done or teams that back into the playoffs who wrapped things up with ease only due to playing in an awful division, end up going all the way. It's really an overrated thing IMO and even though you're obviously coached to put forth your best effort day in day out it just doesn't happen. We clearly weren't up for that game mentally.