Answer based on context:

Trying to rebound from their road loss to the Cardinals, the Steelers went home for a Week 5 interconference duel with the Seattle Seahawks, in the rematch of Super Bowl XL.  Going into the game, Pittsburgh was without Hines Ward, Santonio Holmes, Troy Polomalu, and Casey Hampton, due to injuries. After a scoreless first quarter, the Steelers drew first blood with QB Ben Roethlisberger completing a 13-yard TD pass to TE Heath Miller to lead 7-0 at halftime.  In the second half, Pittsburgh completed the shutout with RB Najeh Davenport running 1&#160;yard for a TD in the third quarter and 5&#160;yards for a TD in the fourth. With the win, Pittsburgh entered its bye week at 4-1.  During the game, the Steelers had over 40&#160;minutes of possession, including 25&#160;minutes of the second half.  In their first five games Pittsburgh had outscored its opponents 57-6 in the first half.  The Steelers also improved to 4-0 on the year when RB Willie Parker has a 100-yard rushing game, as he ran 28 times for 102&#160;yards.

How many players for the Steelers missed the game die to injury?
4