I have a theory.
The problem is that Silf needs time and zero pressure for his shot. Getzlaf's size and reputation as a passer precedes him, and people will rarely take the man - they know to cover his other wingers instead. So the pressure goes on to Silf, who coughs the pucks up or floats a muffin into the goalie.
Kesler, on the other hand, is a center who gathers a lot of respect as a goalscorer, and thrives off of getting up close and personal. So that generates the chaos and most importantly the space for Silfverberg to operate.
It's not enough to have a wicked passer...we need Getzlaf to start actually shooting the puck again. Then people start to respect his shot...which would result in Silfverberg having that time and space.