The Colts (9-5) remain mathematically alive for the AFC's top seed and homefield advantage throughout the postseason, and they can rise as high as the No. 2 seed with victories in their final two games and minimal outside help.
The AFC South champions can do no worse than the fourth seed and a first-round home game regardless of the results in the next two weeks.
"Our goal is just win out regardless," Castonzo said. "Regardless of what happens with anyone else, we want to win the rest of our games and kind of be catching fire here at the right time going into the playoffs. We want to be playing our best ball regardless of what happens with any other teams."