Purifoy signed with the Colts in May after going undrafted out of Florida. Indianapolis' decision to part ways with him was based on a series of "minor, in-house disciplinary issues", according to a report from Stephen Holder of The Indianapolis Star.
Purifoy also had multiple off-field issues during his time with the Gators (2011-13), including a 2013 charge for marijuana possession. He contributed on special teams for the Colts and was expected to possibly earn more time on defense over the final five weeks of the regular season.
This will be Brown's third stint with Indianapolis. The 27-year-old played five games with the team in 2013 and two earlier this season. Brown has also spent time with the Miami Dolphins, who released him earlier this week, and Kansas City Chiefs, who selected him in the fourth round of the 2011 draft.
The Colts (7-4, 1st in AFC South) host the Washington Redskins on Sunday.