Both players missed practice on Friday, and are currently listed as questionable on the team's injury report.
Harrison is recovering from Aug. 15 arthroscopic knee surgery, and did not play in last week's loss to the Denver Broncos.
Polamalu suffered a strained right calf last weekend in the Denver game, and has started in 18 consecutive regular-season games, dating back to 2010.
Harrison and Polamalu have been staples of the dominant Steelers defense for the last eight seasons.
Last week, Harrison was replaced by second-year linebacker Chris Carter. If Polamalu does not play Sunday, veteran Will Allen is likely to fill in.
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