Rusin was called up on Saturday and pitched 3 2/3 innings in relief against the Nationals. It was his second stint with the big league team this year. Rusin also pitched in relief on April 12 against the Cardinals.
The Cubs also placed second baseman Darwin Barney on the paternity list, and they added second baseman Arismendy Alcantara from Triple-A Iowa on Wednesday. Alcantara is ranked as the Cubs' No. 7 prospect and will make his Major League debut on Wednesday. Alcantara was batting .307 with 25 doubles, 11 triples, 10 home runs and 21 stolen bases in 89 games with Iowa.
Barney and wife Lindsay were expecting their third child. Barney returned to Chicago on Wednesday.
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.