Stewart had four total tackles and recovered a fumble in Sunday's win over Chicago.
The Colts agreed to re-sign Stewart on Tuesday to a three-year, $39 million deal, Adam Schefter of ESPN reports.
Stewart racked up 41 tackles (23 solo) and 0.5 sacks across 11 regular-season games with the Colts in 2023.
The NFL suspended Stewart six games for violating the league's PEDs policy, Ben Arthur of FoxSports.com reports.
Stewart recorded seven tackles (six solo) and a pass defended in Sunday's 17-16 defeat against the Commanders.
Stewart tallied 12 tackles (seven solo) during a 19-10 loss to the Titans on Sunday.
Stewart recorded five tackles (four solo) and one sack during Sunday's 34-27 win over the Jaguars.
Stewart had five total tackles, a QB hit and two tackles for a loss in Sunday's tie at Houston.
Stewart (illness) is listed as fully healthy for Saturday's game against New England.