The amount of the one-year contract isn't known at this point, but Rzepczynski filed for $1.3 million while the Cardinals countered with $900,000.
Rzepczynski has spent the past two seasons with St. Louis after being acquired from the Toronto Blue Jays along with Octavio Dotel, Edwin Jackson and Corey Patterson in exchange for Trever Miller, Colby Rasmus, Brian Tallet and P.J. Walters.
Last year for the Cardinals, Rzepczynski maintained an ERA of 4.24 over 70 appearances spanning 46 2/3 innings. After beginning his career as a starting pitcher, he has transitioned into a left-handed specialist with St. Louis. The 27-year-old owns a career 4.04 ERA with 8.1 strikeouts and 4.0 walks per nine innings over parts of four seasons at the major league level.
The Cardinals' agreement with Rzepczynski leaves David Freese as the team's only remaining unsigned arbitration-eligible player.