The Cardinals converted approximately $3.17MM of Patrick Peterson‘s base salary into a signing bonus, according to Field Yates of ESPN.com (on Twitter). The move creates $2.5MM in 2016 cap space. 
The Cardinals are near the bottom of the league in cap room and they needed a bit of a breather in the current year. We are past the trade deadline and there are no real premium free agents left on the board, but the Cardinals should now have enough space to make any minor signings that are necessary for the rest of the season.
Peterson is in the midst of a five-year, $70MM+ extension that was inked in the summer of 2014. That deal now stands as the third-highest in the league amongst cornerbacks in terms of total value and average salary per year. If the full contract is played out, the 26-year-old will not be eligible for free agency until after the 2020 season.
The cornerback got some good news this week when he learned that he did not suffer structural damage to his left knee. Peterson’s knee was hit by the cleat of Falcons receiver Julio Jones on Sunday. The incident was painful, but it doesn’t sound like he’ll miss any time as a result.