SEATTLE -- The Seattle Seahawks placed Marcus Tubbs on injured reserve Saturday, meaning they have lost the hard-luck defensive tackle for the season.
Tubbs left the field on the back of a motorized cart with a right knee injury during the Seahawks' 19-14 exhibition win over Oakland on Thursday.
"It appeared to be rather serious," coach Mike Holmgren said at the time.
He had returned to practice this month for the first time since having microfracture surgery on his left knee last November.
Tubbs, the Seahawks' first-round draft choice in 2004, was an important run-stopper along the defensive line.
The Seahawks on Saturday also traded strong safety Michael Boulware to the Houston Texans in exchange for defensive end Jason Babin.
Twenty-one players were also released. They are CB Omowale Dada, QB Derek Devine, WR Joe Fernandez, DE Brandon Green, DT Marcus Green, CB DeJuan Groce, CB Kevin Hobbs, CB Pete Hunter, LB Cameron Jensen, WR Jordan Kent, FB David Kirtman, TE Joe Newton, FB Josh Parry, WR Logan Payne, C Pat Ross, TE Leonard Stephens, DE Nu'u Tafisi, DT Eric Taylor, G Steve Vallos, RB Marquis Weeks and T Kyle Williams.
Copyright 2007 by The Associated Press. All Rights Reserved