The quarterback is the most important position in football. Whether you consider it fair or unfair, teams live or die based on how the quarterback performs. Even the best defenses in the NFL will lose at some point if their quarterback can’t perform (see: Houston Texans 2015 season).
The Jacksonville Jaguars do not have a great defense to rely on (though recent changes in the secondary should help) and this puts even more pressure on the quarterback position.
With the recent changes across the defense and additions of new players still to come through the 2016 NFL Draft, the Jaguars are expected to take a step forward.