Although the tight end is the primary receiver, the quarterback has the option to throw the ball to the other receivers in the pattern, especially the "go" route if the cornerback is playing bump-and-run coverage on the flanker and the QB likes the matchup of his WR against the DB.
Roman called a Y-Stick. Alex Smith noticed Richard Sherman was giving flanker Michael Crabtree a 10-yard cushion. Smith, without ever looking at Davis, took a three-step drop and fired a short pass to the sideline. Smith expected Crabtree to run a quick out, but he ran a "go" route up the field and the pass fell incomplete.
I don't know who takes the blame for that busted play, because I don't know if Crabtree was supposed to change his route.
On the next play Joe Staley was flagged for a false start, and then the 49ers faced third and 12. Roman called another Y-Stick play – this time from a spread shotgun formation. Davis lined up as a receiver in the slot right next to the right tackle. He ran a quick stick route and was open, but Smith didn't throw it to him. Instead, Smith stepped up in the pocket and threw a 2-yard check down pass to Frank Gore, and then the 49ers punted.
http://49ers.pressdemocrat.com/2012/10/inside-the-49ers/did-roman-call-the-y-stick-and-the-y-stick-lookie-against-the-seahawks/
, that's why the passing game is off and on, when Alex has all the pieces set in place, blocking, WR's open and playing calling is on fire, he plays like a top 10 QB. He needs to be confident, or we see him getting back to his old self. Vernon was getting the ball pretty often when we were on our terror through the first 4 games.
