The 29-year-old Schlitter joins the Cubs for his second stint in the big leagues this season, as he went 0-2 with a 9.53 ERA (6 ER/5.2 IP) in seven appearances during his first stay from April 10-April 26. He has no record with two saves and a 0.00 ERA (6.0 IP) in six relief appearances with Iowa this season.
Schlitter went 2-3 with a 4.15 ERA (26 ER/56.1 IP) in 61 appearances for the Cubs last season, his first big league action since the 2010 campaign. He turned in a 2.98 ERA (14 ER/42.1 IP) in 43 appearances prior to the All-Star Break before being slowed by right shoulder inflammation that led to a stint on the disabled list in August. Overall, he allowed one earned run or less in 54 of his 61 appearances, including 48 scoreless outings.
The righthander was originally selected by the Philadelphia Phillies in the 16th round of the 2007 Draft and acquired by the Cubs the next season for lefthander Scott Eyre. Schlitter made his big league debut in 2010 with seven relief appearances. He is a native of Oak Park in suburban Chicago.
Szczur, 25, is batting .172 (5-for-29) with two doubles and five RBI in 18 games with the Cubs this season. With Iowa, Szczur has batted .262 (11-for-42) with two homers, a triple and seven RBI in 11 games this year.