Wood was 0-3 with a 5.63 ERA in 13 relief appearances for the Pirates this season. He was designated for assignment by Pittsburgh last Friday in order to reinstate pitcher Ross Ohlendorf from the 60-day disabled list.
In 40 games with Triple-A Indianapolis, Wood went 2-0 with 23 saves and a 2.84 ERA.
The 28-year-old Wood has been added to the Rangers' 40-man roster and optioned to Triple-A Round Rock.
Originally selected by Florida in the 44th round of the 2002 draft, Wood has a record of 1-4 with a 4.50 ERA over 57 career relief appearances in the big leagues with the Marlins (2009-10) and Pirates (2011).