The 49ers had already ruled out wide receiver Ricky Pearsall, who missed practice all week with knee and ankle injuries.
“He was close,” coach Kyle Shanahan said after the team’s final practice of the week. “But not close enough.”
Cornerback Renardo Green (neck) was also ruled out Saturday.
The team did activate defensive lineman Yetur Gross-Matos (hamstring) from injured reserve, and he will play. The 49ers also activated cornerback Eli Apple and linebacker Eric Kendricks from the practice squad to play tonight.
The 49ers’ other inactives are defensive lineman Kevin Givens, running back Isaac Guerendo, cornerback Chase Lucas, defensive lineman Robert Beal Jr. and linebacker Curtis Robinson.
The Colts’ inactives are linebacker Jaylon Carlies, cornerback Sauce Gardner (calf), running back DJ Giddens, wide receiver Anthony Gould (foot), safety Reuben Lowery III, tight end Will Mallory and offensive tackle Bernhard Raimann (elbow).
Defensive tackle DeForest Buckner was activated from injured reserve and will play.