Clark will earn about $17.1 million if he signs and plays under the tag in the 2019 season. Seattle used the non-exclusive franchise designation on Clark, meaning the defensive end is allowed to negotiate with other teams.
If Clark signs with another franchise, his new team will owe the Seahawks two first-round draft selections. It is the first time Seattle has used the franchise tag since tagging kicker Olindo Mare in 2010.
The Seahawks and Clark have until July 15 to work out a long-term contract extension. Seattle head coach Pete Carroll said he hopes to have Clark as the sides work toward a suitable deal.
"It is ultimately [the goal], yeah," Carroll told the team's official website. "Frankie just turned 25, he's still a very young football player. Made a huge step this year in terms of leadership, growth and maturity. It was so obvious. I was really proud of seeing that develop for Frank. He played great, too. Frank, he's a very valuable football player and that's the process we're in the middle of and all that. I can't tell you guys how that's going to turn out, but it's going to be positive for the Seahawks and for Frank."
The Seahawks selected Clark in the second round of the 2015 NFL Draft out of Michigan. He had 41 tackles and a team-high 13.0 sacks while starting 16 games last season.
In his four-year career, Clark has 136 total tackles, 35.0 sacks, eight forced fumbles, one interception and six passes defensed.
The NFL's deadline for teams to use the franchise tag is Tuesday at 4 p.m. EST.