A statement issued by officials of Reliant Park said the fan fell from the escalator and was taken to a hospital, but did not give information about the fan's condition.
Houston police spokesman Kese Smith said the fall occurred at the north end of the stadium and the fan's condition wasn't known.
In 2011, a firefighter attending a Texas Rangers game in Arlington died when he fell from the left field stands while reaching for a baseball tossed his way by All-Star outfielder Josh Hamilton.
Shannon Stone fell about 20 feet onto concrete when he tumbled over the left-field railing after catching the ball and falling into an area out of sight from the field as the Rangers faced Oakland. Cooper Stone, his 9-year-old son, witnessed the fall during the second inning.
In April, a statue of Stone and his son was dedicated to Rangers fans in front of the home plate gate at Rangers Ballpark in Arlington. Railings also were raised throughout the ballpark before this season.
In 2010 at Rangers Ballpark, a fan fell 30 feet from the second deck while trying to catch a foul ball. Tyler Morris suffered a fractured skull and sprained ankle.