ARLINGTON -- On the night the Rangers signed Roy Oswalt, the pitcher he will likely replace in the rotation faltered in the fifth inning once again.Despite an ailing Josh Hamilton hitting his Major League-leading 21st home run of the season, a two-run shot in the sixth, the Rangers' four-game winning streak was snapped on Tuesday. Hamilton drove in all of his team's runs while Scott Feldman lasted 4 2/3 innings, allowing four runs (two earned) on four hits as the Rangers lost to the Mariners, 10-3, at Rangers Ballpark. "I thought he threw more strikes than he did in the past. It was quite an improvement," manager Ron Washington said of Feldman. "It seemed like he hit a little wall there where he couldn't execute his pitches the same way that he was executing them earlier." In each of his past three starts, Feldman has been pulled in the fifth inning and the Rangers have lost. This time, it was a throwing error with the bases loaded by third baseman Adrian Beltre that allowed two runs to score, ending Feldman's night. He fell to 0-3 on the year. "I don't think I've been hitting a wall. A couple weird things have happened," Feldman said. "I'm trying to leave everything on the field, but I feel like I could go out there for 120 pitches. Three times that's happened, that's a lot, I know. But I do think that's a coincidence." The Rangers announced the acquisition of Oswalt on Tuesday night. Oswalt, 34, agreed to a Minor League contract, pending a physical, and will not immediately join the 40-man roster. He will make his first start for Triple-A Round Rock on Saturday night against Albuquerque. "When everybody gets healthy, we're going to have a very deep pitching staff," Michael Young said. "It's a great sign for the organization. I have a lot of at-bats against Roy, and I have a lot of respect for him." While Oswalt prepares for his 12th season in the big leagues and Neftali Feliz recovers from right elbow inflammation, Feldman will remain in the Rangers rotation. But when either suits up in Arlington, Feldman will likely go back to his place in the bullpen. "Hopefully he'll be the Roy that we know he can be," Mike Adams said. "We know management is going to do the best they can to put the best team out there. If they think we're a better team with Roy Oswalt, then that's why they got him. We'll see how it plays out." Elvis Andrus doubled and scored on an RBI groundout by Hamilton in the first inning. But that 1-0 lead did not last long. After Justin Smoak reached on a fielder's choice in the second inning, Feldman surrendered a two-run home run to John Jaso with two outs. Feldman, who sat down the first four hitters of the game, retired six in a row after allowing the home run to Jaso and kept the Mariners from scoring again until the fifth. That's when Brendan Ryan doubled and Dustin Ackley drew a walk with one out. After Alex Liddi, who ended Feldman's last outing with a grand slam, struck out, Ichiro Suzuki was intentionally walked to load the bases. Jesus Montero followed with a ground ball between third base and shortstop, which was stabbed by Beltre, who fired wide of first baseman Mike Napoli. The ball bounced in and out of the Rangers' dugout as Ryan and Ackley scored to put the Mariners up, 4-1. Feldman, having thrown a season-high 88 pitches, was then replaced by Robbie Ross. Hamilton trimmed that lead to 4-3 with his home run in the sixth. Andrus led off the inning with a single up the middle past a diving Ackley at second base. He trotted home when Hamilton sent a first-pitch, 87-mph fastball from Justin Vargas 409 feet over the center-field wall. Hamilton, who missed Monday's game with an upper respiratory infection, leads the Major Leagues with 56 RBIs. "He got us right back in the ballgame," Washington said. "It's Josh Hamilton. He went out, he worked, he said he felt good enough to play, and he delivered three runs for us. But it just wasn't enough because we couldn't get anything going." The Mariners added six more runs in the eighth, sending 10 batters to the plate. The first four recorded base hits, with a leadoff double by Kyle Seager followed by three straight singles. An error by shortstop Andrus allowed another run to score before two more singles from Ackley and Liddi. After seven straight Mariners reached base against Alexi Ogando and Mike Adams, the next three were retired by Mark Lowe to end the inning. "Ogando and Adams, those are not guys you're hoping to see on the mound," Ryan said. "Those are not comfortable at-bats. So to scratch a couple across, let alone that many, that was nice."
Christian Corona is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.