Houston Texans star running back Arian Foster has been ruled out for Sunday's game against the Arizona Cardinals due to a back injury suffered against the Indianapolis Colts.

The injury is regarded as serious, according to sources.

Foster has been dealing with a hamstring injury previously. Now, he's hampered by the back problem.

Foster has also had a calf injury this season, but has managed to rush for 542 yards and one touchdown in eight games this season while fighting through the pain.

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Aaron Wilson covers the Ravens for The Baltimore Sun.