Reed missed the first two games of the regular season and was sidelined for the entire preseason.
For the Ravens, running back Ray Rice has been scratched due to a strained left hip flexor that's regarded as a two-week injury, with the defending Super Bowl champions hoping to get him back on the field next week against the Buffalo Bills.
A 2004 NFL Defensive Player of the Year, Reed had surgery this offseason after leaving the Ravens in March to sign a three-year, $15 million contract with the Texans. Reed is the NFL active leader with 61 interceptions for 1,541 return yards and seven run back for touchdowns.
Instinctive and unpredictable, Reed has game-changing ability, but the 35-year-old's durability and age have been working against him in recent years.
The Ravens also scratched Pro Bowl kick returner Jacoby Jones (sprained right medial collateral ligament), defensive lineman Chris Canty (groin), inside linebacker Arthur Brown (strained left pectoral), wide receiver Deonte Thompson (left foot sprain), defensive tackle Brandon Williams (right big toe) and center Ryan Jensen (foot surgery).
Cornerback Chykie Brown is active after being listed as questionable on the injury report. He told The Baltimore Sun this week that he's "good to go for Sunday."
The Texans also scratched: quarterback Case Keenum, defensive end Sam Montgomery, offensive lineman Cody White, offensive tackle Duane Brown, wide receiver Lestar Jean, linebacker Justin Tuggle and defensive end Tim Jamison