The 30-year-old Gill is replacing defenceman Nick Grossmann, who injured his right knee in the Flyers' 2-1 home win on Friday in Game 4. The series is tied 2-2.
Gill played in only six games during the regular season, but he has been in 110 career playoff games in 16 NHL seasons.
Carcillo played in the previous two games after sitting out the first two. Miller, who had three goals and three assists in 30 games this season, is making his post-season debut.