In 2018, the Seahawks mostly had five receivers active for game days. I do not expect 2019 to be any different, though the reason they might have six active is because Doug Baldwin is no longer on the team. Building trust between Russell Wilson and his receiving corps is a must. And Baldwin was trusted the most.
Wilson and Tyler Lockett combined to have a perfect quarterback rating when Wilson targeted Lockett last season. Lockett, however, still was not targeted enough so it remains to be seen just how many more targets Lockett gets this coming season and how much Wilson trusts Lockett in times of crisis.