Parker, 28, last season posted a 2.72 ERA (14 ER/46.1 IP) and was 1-2 with a save in 49 relief appearances for Chicago following his promotion from Iowa on June 1. He averaged 10.7 strikeouts per 9.0 innings pitched, striking out 55 in 46.1 innings. In 26 games against N.L. Central division opponents, Parker posted a 2.31 ERA (6 ER/23.1 IP).
Since making his major league debut with the Cubs in 2012, Parker is 1-2 with one save and a 3.10 ERA (18 ER/52.1 IP) in 56 career relief appearances for Chicago. He has walked 20 and struck out 61 in 52.1 innings pitched, good for an average of 10.5 strikeouts per 9.0 innings.
Parker began this season with Iowa, throwing 3.0 scoreless innings with one save in three outings. The righthander owns a 3.35 ERA (74 ER/199.0 IP) in 159 career relief appearances with Iowa, and holds the all-time franchise record with 42 saves.
Since he was selected by Chicago in the 16th round of the 2006 draft, Parker is 14-17 with 67 saves and a 2.95 ERA (114 ER/347.1 IP) in 260 career minor league contests, all in relief. He has walked 165, struck out 376 and allowed just 25 home runs.
Rusin, 27, was recalled prior to yesterday's game in St. Louis and allowed one run in 5.0 innings out of the bullpen. He is 0-2 with a 6.52 ERA (7 ER/9.2 IP) in two starts for Iowa this season.