Smith hurt his left biceps during a 24-10 win over Atlanta on Sunday. The Bengals (2-0) also are missing tight end Tyler Eifert, who is out for at least eight games with an elbow injury.
The Bengals signed free-agent tight end Kevin Brock to fill Smith's spot. The second-year player opened camp with Cincinnati and was waived on Aug. 26. He has played in six games with Buffalo and Kansas City.
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