Brown, who led the team with eight interceptions last season, tied for second in the NFL, appeared to be hurt when he was tackled after a 22-yard return. The four-year veteran could not put any weight on his leg.
The Giants also lost backup cornerback Jayron Hosley with a sprained ankle in the quarter.
Giants coach Tom Coughlin had no immediate updates on his team's injuries.
AP NFL website: www.pro32.ap.org
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