The Broncos would have seven days to match any offer sheet Marshall signs. If Denver opted not to, the Broncos would receive the sixth overall pick in the April NFL draft.
However, Marshall is not expected to sign an offer sheet Saturday with Seattle, league sources said.
The visit is not meant as an immediate step toward a signing; rather it's a get-to-know-each other visit in a process that is not expected to be quick.
The Seahawks have several reasons for showing interest in Marshall beyond his potenial production.
The Seahawks have two first-round picks, including the 14th overall pick they acquired from Denver last April.
And Seattle's offensive coordinator is Jeremy Bates, who worked with Marshall in Denver; the Seahawks' receivers coach is Jedd Fisch, who also worked with Marshall.
Marshall turns 26 later this month. He has had three straight seasons with more than 100 catches.
Adam Schefter is ESPN's NFL Insider.