Indianapolis originally signed Johnson on Friday then released him Monday. With Luck still limited in practice and backup Matt Hasselbeck sitting out Tuesday because of illness, the Colts (2-2) brought back Johnson in time for Thursday night's game at Houston (1-3).
To make room on the roster, Indy put cornerback Jalil Brown on season-ending injured reserve with a groin injury.
On Tuesday, Luck said he was preparing as if he would start against the Texans. Coach Chuck Pagano said Luck has looked good in his limited work this week.
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