Jonathan Taylor rushed for 137 yards and a touchdown on 15 carries in the first half.
The rookie running back has the Colts leading the Jaguars 20-7 at halftime.
The Colts scored on four of their six possessions, punting once and having Rodrigo Blankenship miss a 56-yarder on the final play.
Rivers completed 10 of 15 passes for 93 yards in the first 30 minutes.
Nyheim Hines has two carries for 17 yards and six catches for 50 yards.