Mike Mularkey: Justin Blackmon alternates between great and lost

Jaguars coach Mike Mularkey says first-round receiver Justin Blackmon looks about the way you’d expect a Top 5 rookie draft pick to look at the start of Organized Team Activities: Flashes of talent mixed with flashes of incompetence. “When he knows what he’s doing, he’s very good,” Mularkey said. “When he doesn’t, he’s lost.” Those…