The veteran tight end immediately knew something was wrong, hopping on one foot following a non-contact injury before he finally went down and was not able to get off the field on his own.
The Seahawks feared Olsen ruptured his plantar fascia.
Those fears are confirmed.
NFL Network Insider Ian Rapoport reported Friday on Good Morning Football that Olsen did indeed suffer a rupture of his plantar fascia, an injury that will knock him out for two months or so, at least, per sources informed of the situation.
Rapoport added that the hope is Olsen could come back, but it would take a deep Seahawks playoff run, potentially one that reaches the Super Bowl, for that to happen.
Coach Pete Carroll said after the game that the team is unsure whether Olsen could return but was optimistic given that it's an injury the tight end has dealt with in the past.
"I don't know that yet," Carroll said, via ESPN. "There's been some marvelous returns for guys who do rupture their fascia that would blow you away. Right now, he's in really a lot of discomfort and all that. But we'll see what happens. I can't tell you anymore. It's pretty early to be talking about it."
If Olsen is unable to return, it could spell the end of a great 14-year NFL career. The 35-year-old considered making the move to the broadcast booth last offseason before signing in Seattle. It'd be a brutal way to end for a player who has continued to push through injuries down the stretch run of his stellar career.