Schlitter was available in Sunday night's game against the Cincinnati Reds.
In nine appearances with the Cubs this season, Schlitter has allowed six runs in 6 2-3 innings with an 0-2 record. He gave up two runs over 13 innings in 14 relief appearances for Iowa.
To make room for Schlitter, the Cubs optioned outfielder Junior Lake to Iowa. In 21 games with the Cubs, he hit one home run with a .224 batting average.