Ninja explained it very well. Murray is dr. jekyll/mr. hyde indeed. A lot of Andy Dalton in him. When things are going good he is competent and will even confuse people into thinking he is a franchise QB. Unfortunately, when he is forced to get uncomfortable he doesn't handle it well at all. His field vision completely disappears and he makes some extremely bad reads/throws that make you wonder what the heck he was thinking or seeing when he threw the ball.

 

I think he is the perfect definition of QB purgatory. If he winds up on a good team with a good supporting cast he will probably be able to not screw things up too badly and probably even be able to 'lead' that team to the playoffs. Just like Dalton, however, it is fools gold. If you will be happy with a lot of one and done's in the playoffs (and that is if you have a very good supporting cast to begin with) then Murray is your guy. 

 

To me the ideal outcome if the Jags took him would be to hope to 'develop' him and hope he shows well in limited preseason/low leverage regular season games a year or two down the road, then try to trade him for a profit before his purgatorial traits show too much. Much like what the Redskins could have done with Cousins before they exposed him too much and killed his perceived value.

---