he's had some rough injuries since the end of last year. Quarterbacks have bad years, I expect him to rebound at some point. I thought Bortles was given a bad rap after his horrible year last year as well. Look at Dak this year, he's basically been Tyrod (who's had his worst career year as well IMO).
It's a combination of injuries, talent surrounding quarterbacks, and just having your head in the right place. Quarterback has to be one of the toughest jobs in team sports mentally. I've always had a preference for veterans who have at least shown they can play at that kind of pressure for a year or two, than throwing in an unproven rookie mid year to see what sticks.