Rusin, 27, has spent the majority of the season with Iowa, going 7-11 with a 3.76 ERA (51 ER/122.0 IP) in 19 starts. He threw a 9.0-inning no-hitter, May 7 in New Orleans - the team's first no-hit effort since Reggie Patterson accomplished the feat, August 21, 1984 against Omaha - which earned him Pacific Coast League Pitcher of the Week honors for May 5-11. Rusin has pitched at least 6.0 innings in 17 of 19 starts, and has walked two or fewer in 15 outings.
Rusin has no record and a 6.23 ERA (6 ER/8.2 IP) in two relief appearances over two stints with the Cubs this season. He was recalled from Iowa, April 12, and allowed one run in 5.0 innings of relief that day in St. Louis before he was optioned following the game. He was promoted again, July 5, and allowed five runs in 3.2 innings of relief that day in Washington before he was optioned back to Iowa, July 8.
In parts of three major league seasons with Chicago beginning in 2012, Rusin owns a 4-9 record with a 4.82 ERA (56 ER/104.2 IP) in 22 games, all but two as a starter. Last season, he recorded 22.1-consecutive scoreless innings on the road from July 27-September 12, a franchise mark for left-handed rookie pitcher.
Originally selected by Chicago in the fourth round of the 2009 Draft, Rusin owns a 37-39 record with a 3.73 ERA (278 ER/671.0 IP) and two complete game shutouts in 124 career minor league games, all but seven as a starter. He was named a 2013 Pacific Coast League All-Star.
Parker, 29, is 1-0 with a 5.59 ERA (6 ER/9.2 IP) in seven games spanning four stints with the Cubs this season. He has spent the majority of the year with Iowa, posting a 1.29 ERA (4 ER/28.0 IP) with a Pacific Coast League-leading 21 saves in 28 games.