Cook caught 30 balls for 377 yards and a touchdown in 10 regular-season games with the Green Bay Packers last year. He played well in the playoffs, totaling 229 yards on 18 catches in three games.
The Seahawks are in a tricky spot at the tight end position. Jimmy Graham is entering the final year of his contract, and he's not going anywhere this offseason. The Seahawks paid Graham a $2 million roster bonus on Saturday. He had 923 receiving yards last season (third-best among tight ends) coming off of a ruptured patellar tendon injury, and by all accounts, Graham is expected to be a big part of the offense in 2017.
Luke Willson and Brandon Williams, meanwhile, are free agents. And the only tight end on the roster who is signed beyond next season is Nick Vannett. A third-round pick last year, Vannett didn't contribute much in 2016, but he is still expected to have a role going forward.
One factor in the Seahawks' interest in Cook could be Russell Wilson's effectiveness out of two tight end sets last year. He completed 73.7 percent of his passes (third), averaged 10.27 YPA (third) and posted a QBR of 88.7 (second) when the Seahawks went with two or more tight ends. Overall, 18.6 percent of Wilson's dropbacks came out of two (or more) tight end sets. The Seahawks could be looking to bump that number up in 2017.
Doug Baldwin, Graham and C.J. Prosise figure to factor prominently in the passing game. And Paul Richardson came on down the stretch last year. But perhaps the Seahawks are looking for more pass-catching options.
Last year, Cook signed a one-year, $2.75 million deal with the Packers, and he'll almost certainly be looking for a raise.
A couple days ago, Seattle had a significant chunk of money allotted for T.J. Lang, but Lang ended up signing with the Detroit Lions. The Seahawks may now be checking out free agents whom they previously didn't think would fit in their budget.
NFL Network was first to report the Seahawks' interest in Cook.