Armando Galarraga has been called up to the majors.
Galarraga, of course, is the righty pitcher who came over with Brad Wilkerson in the Alfonso Soriano deal, and who had a nice bounceback season at AA in 2007 after a disappointing 2006.
My guess is, after the doubleheader, and with the injury issues with Luis Mendoza, Kam Loe, and Scott Feldman (plus Bill White being away from the team), the Rangers just want to make sure they have a spare arm in the bullpen in case of emergency.