Rangers purchased the contract of RHP Roy Oswalt from Triple-A Round Rock. He replaces the injured Mitch Moreland (hamstring) on the active roster and will make his Rangers' debut Friday night against the Rockies. Oswalt, who signed with the Rangers late last month, had a 5.87 ERA and 13/4 K/BB ratio over four tuneup starts between Double-A Frisco and Triple-A Round Rock. He's coming off a 3.69 ERA, 1.34 WHIP and 93/33 K/BB ratio in 139 innings last season with the Phillies. His velocity and strikeouts were down last year and he's pitching full-time in the American League for the first time in his career, so temper expectations in shallow mixed leagues.