He violated the league's substance abuse policy.
The best guy after that is likely to be fourth-round draft pick Ace Sanders from South Carolina, a small slot guy at 5-foot-7 and 173-pounds.
Jacksonville's first five games are against Kansas City, at Oakland, at Seattle and against Indianapolis.
The Jaguars are planning on staying out West between the games against the Raiders and Seahwaks. So beyond missing four games, Blackmon will miss a big bonding week on the road.