The Rangers, who acquired Jeffress last year in a deadline deal that also sent catcher Jonathan Lucroy from Milwaukee to Texas, received right-hander Tayler Scott in the deal.
Jeffress, 29, has a 5.31 ERA in 39 relief appearances this season for the Rangers and has allowed a home run in each of his past four appearances. He made his major league debut with the Brewers in 2010 before being traded to Kansas City that offseason. Jeffress also spent time with Toronto before Milwaukee brought him back as a free agent two years ago.
Scott, 25, is 4-6 with a 2.34 ERA in 42 appearances for Double-A Biloxi.
The Associated Press contributed to this report.