The Steelers listed Parker as doubtful, but players who do not practice almost never play for them. Parker may attempt to run during a special teams practice Saturday.
Parker injured his left big toe -- an injury commonly known as turf toe -- in Cincinnati on Sunday and did not practice all week. Parker ran for 146 yards and two touchdowns as the Steelers beat San Diego 35-24 in the divisional playoffs last season and 115 yards in Pittsburgh's 11-10 victory during the regular season.
Parker is expected to be replaced by Rashard Mendenhall, who was benched by coach Mike Tomlin in Cincinnati except for special teams because he didn't correctly run plays in practice. Mewelde Moore, normally the third-down back, is expected to get additional carries.