Second baseman Emilio Bonifacio was activated from the disabled list to take Barney's place on the roster. Bonifacio had been out since June 13 because of strained right oblique.
The 28-year-old Barney won a Gold Glove in 2012, when his 141 consecutive games without an error tied a major-league record. But he regressed noticeably at the plate and, with the recent promotion of Arismendy Alcantara and other infield prospects on the way, he no longer fit the master plan.
''He got in a position here where playing time started to be scarce for him —whether it was (Luis) Valbuena, whether it was Bonifacio or it was Alcantara —and that necessitated the move,'' general manager Jed Hoyer said. ''It certainly wasn't easy. He is such a great guy and a great competitor, and hopefully, through this process, we can get him to a place where he can help a contender and get a feel for a pennant race.''
Barney was hitting .230 with two home runs and 16 RBI in 72 games. Last season he hit .208 with six home runs and 41 RBI in 141 games, all except two as a starter.
The Cubs have 10 days to trade or place Barney on unconditional waivers. If he clears waivers, the team can release him.
Earlier this month, veteran pitcher Jason Hammel and Jeff Samardzija were dealt to the Oakland Athletics highly regarded shortstop prospect Addison Russell. More moves were expected in the weeks ahead for the 40-57 Cubs.
Also, pitcher Kyle Hendricks was recalled from Iowa and pitcher Zac Rosscup was optioned to the Triple-A club. Hendricks was the scheduled starter for the game against the San Diego Padres on Tuesday night.