Jackson struggled through his rookie year but held on to his starting spot through the preseason despite a strong challenge from Allen.
The Texans' secondary was picked apart in second half by Drew Brees last week in New Orleans in a loss to the Saints. Jackson was not good, but plenty of other defenders were victimized as well.
Allen will line up across from speedy receiver Mike Wallace, and should get significant safety help.
The complete list of inactives:
QB T.J. Yates
CB Kareem Jackson
RB Derrick Ward