Parkinson's signing was listed on the official NFL transactions on Tuesday.
Seattle made eight picks in the April draft. Parkinson was taken with the first of Seattle's two fourth-round selections.
At 6-foot-7, Parkinson is another tall target for quarterback Russell Wilson, especially in red-zone situations. Parkinson had 48 receptions and just one drop in his final season at Stanford. He had just one touchdown last season but had seven TD catches in 2018.
Parkinson is part of a loaded tight end group that includes Greg Olsen, Will Dissly, Jacob Hollister and Luke Willson.
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