Why is Jair Jurrjens so underrated?

He is underrated I agree, but if season ended today Halladay would still win cy young off of him, because Halladay has much more stats to look at you can not just look at ERA, Jurrjens doesn't go that far in games, that's why his ERA is so low and when he is in trouble they just take him out and bullpen gets out of it, this reminds me of last years Ubaldo Jimenez