Catcher Chris Gimenez was placed Monday on the paternity list, where he can be up to three days.
The moves were made before the Rangers' game at the Chicago White Sox, a day after Texas got Carp on a waiver claim from Boston.
Carp hit .198 without a homer and nine RBIs in 42 games this season for Boston. He is a career .260 hitter in 301 major league games with Seattle (2009-12) and Boston (2013-14).
Left-hander Ryan Feierabend was assigned outright to Triple-A Round Rock, where he made 19 starts before getting called up July 12. He made six relief appearances for Texas, which designated him for assignment on Friday.