The incident occurred when Tate was blocking in a screen pass for one of his fellow receivers and he knocked Lowery to the ground, which caused him to hit his head off the turf and resulted in a concussion.
Seattle were not penalised on the field by the officials, however on review the league decided that the hit by Tate was worthy of a hefty fine.
Seahawks head coach Pete Carroll told reporters: "It's very unfortunate. It was a really good block and it was unfortunate for the kid that he was in position to get hit so hard, but the intent was to lay a block, that just happened to occur in the heat of the moment."
Tate was fined for a similar hit last year on Dallas Cowboys linebacker Sean Lee.