Axford served as the Brewers closer from 2010-2012, compiling 105 saves for Milwaukee over three seasons. He began the 2013 campaign in the closer's role, but struggled to begin the year and was moved to set-up man.
The right-hander carried a 9.00 ERA in mid-May, but has settled down recently, posting a 2.70 ERA over his last 40 innings. Overall, Axford has a 4.45 ERA over 54 2/3 innings with 54 strikeouts and 23 walks.
St. Louis enters Friday with a 3.56 ERA from their relievers, the eighth-best mark in the NL. Acquiring Axford gives the Cardinals some insurance for closer Edward Mujica while giving the team more flexibility.
The Axford addition allows St. Louis to move one of their young starters, most likely Michael Wacha, out of the bullpen and into the rotation, according to Derrick Goold of the St. Louis Post-Dispatch. Mujica has also been battling "arm fatigue," so Axford may close games if Mujica is unavailable, though, Trevor Rosenthal remains an option as well.