For now, Dissly is the number one tight end on the roster. However he could be the fifth tight end on the roster and the Cardinals would likely have difficulties covering him.
As it stands now, he has 12 receptions for 124-yards and 3 touchdowns. He may get some reprieve this week with the addition of tight end Luke Willson. Willson just re-signed with the Seahawks this week.
It is probably no coincidence Willson signed this week in particular, given the Cardinals lack of ability to cover any tight ends. Dissly has his 3 touchdowns though, so Russell Wilson is looking for him.
While Willson does have 2 touchdown receptions against the Cardinals lifetime himself, Dissly should still be the go-to guy. But now they have multiple tight end targets that can hurt the Cardinals.
We should all fully expect one or both of them to do some damage on Sunday. So far, there has been no indication the Cardinals are going to fix their tight end coverage anytime soon.