Feldman, however, has been hit hard in his last three starts against the Athletics heading into Monday night's opener of a four-game set at the O.co Coliseum.Texas (32-22) signed Oswalt to a minor-league deal last Tuesday, and he figures to be in Arlington before the end of June. Now there is more pressure on Feldman (0-3, 4.50 ERA), who has failed to last past the fifth inning in his first four 2012 starts.The right-hander has dropped his last three outings, yielding four runs over 4 2/3 innings in Tuesday's 10-3 defeat to Seattle. He is only in the rotation because Neftali Feliz is on the disabled list."I don't really have a reaction to it," Feldman said about the Rangers adding Oswalt. "I just work here, and do what I'm told to do here."Feldman hasn't started against the Athletics (23-31) since 2010, going 0-3 with a 10.80 ERA in his last three starts in the series. He has fared well against Oakland regulars Kurt Suzuki, who is 4 for 16 against him, and Cliff Pennington, who is 2 for 11.Suzuki is in a 3-for-31 slump and Pennington is hitless in his past 29 at-bats for the longest drought of his career. They are part of the reason why Oakland has been shut out in three of its last four games and is hitting .209 for the majors' worst mark.Oakland fell 2-0 in Kansas City on Sunday. The A's have scored 21 runs during a 1-10 stretch -- and that includes a nine-run outburst in the lone victory in that run Saturday."It's been definitely a tough stretch," Pennington said. "We played pretty well earlier in the year and lately, we haven't been getting the hits like we were. We've just got to start getting that big hit."The poor offense continues to heap pressure on Oakland's starters, with Jarrod Parker (1-2, 2.88) allowing one run in 13 innings over his two previous outings and receiving no decision both times. Parker's six scoreless innings Tuesday at Minnesota were wasted when closer Brian Fuentes blew a save in a 3-2 defeat.The right-hander has never faced the Rangers, meaning he'll get his first look at Josh Hamilton.The Texas slugger, who leads the majors with 57 RBIs, did not drive in a run in a series for the second time in 2012 over the weekend as his club dropped two of three to the Angels. The first time was when Texas and Oakland split two games in Arlington from May 16-17.The Rangers ended a season-high four-game slide with Sunday's 7-3 victory. They were buoyed after manager Ron Washington addressed the club in a postgame meeting Saturday that included advice from a female fan who handed him a letter during that night's 3-2 defeat."We just had to get back to who we are," Washington told the Rangers' official website. "Play the game with fun and play the game with aggression. That's what we did."Texas has taken 13 of the last 16 meetings with Oakland, including five of six on the road.The Rangers lead the majors with 302 runs while the A's are last in the AL with 173.