Oswalt was rocked for a season-high eight runs, including seven earned runs, and he gave up a 468-foot home run to Josh Hamilton as Texas slammed the Astros, 10-1, in the Interleague finale for both teams at Rangers Ballpark in Arlington.
"Just kind of missed my spots pretty much and threw it over the middle of the plate," said Oswalt, who made his first start against the Rangers since Texas club president Nolan Ryan acknowledged last week the team had an interest in acquiring him. "They're a pretty good offensive club, but if you miss over the plate it doesn't matter if you're throwing against a Double-A team, you're going to get hit."
The Astros finished Interleague Play 3-12 and went 1-5 against the Rangers, who improved to 46-29 for their best record after 75 games in team history. The Rangers outscored the Astros, 40-18, in their six games, improving to 33-27 all-time against their intrastate rivals.
Six of the Rangers' 11 hits went for extra bases, with Hamilton's mammoth blast in the second inning giving Texas a 2-0 lead and extending his hitting streak to a career-high 21 games, six of which have been against Houston. Michael Young also homered for Texas.
"They just pounded the ball," Astros first baseman Lance Berkman said. "They've got a great lineup, and I expect them to be right there at the end of the year."
Oswalt (5-10), who had 13 quality starts in his first 15 outings, is two losses shy of tying his career high and remains two wins short of tying Joe Niekro's club record of 144. He gave up seven hits and season highs in runs, earned runs and walks (four) in just 4 2/3 innings, which is his shortest start of the season in which he didn't get ejected.
The seven earned runs allowed were his most since giving up eight in a loss to Florida on April 11, 2008. Needless to say, the Astros haven't seen Oswalt struggle this much in a long time.
"I don't think anyone has, and that's one of the most surprising things about tonight," Houston manager Brad Mills said. "They seemed like they were able to be patient on him. ... But they set back and they hit him pretty good."
Oswalt enjoyed a 1-2-3 first inning before things started to unravel in the second. Vladimir Guerrero led off the second with a double off the left-field wall, and Hamilton crushed a 1-1 pitch from Oswalt into the upper deck in right-center field for a two-run homer. It was the second-longest homer in ballpark history.
"It was supposed to be inside," Oswalt said. "I was actually going to throw about two balls off the plate inside and it came back over the white part of the plate. You miss over the plate you're going to get hit."
Young homered with one out in the third, and Ian Kinsler followed with a double and scored on a two-out error by third baseman Chris Johnson to give the Rangers a 4-0 lead. Elvis Andrus reached out and poked an RBI single into right in the fourth to make it 5-0. The rout was on.
"We battled Oswalt," Rangers manager Ron Washington said. "We got him out of there before he could finish five. We got his pitch count up in the heat. But even though we got him up to 100 [pitches] through 4 2/3, he still looked like he had something left."
The Astros got on the board in the fifth on an RBI single by Michael Bourn, but Oswalt wouldn't survive the inning. He gave up three walks and threw two wild pitches before being pulled after a two-run single by Matt Treanor stretched the lead to 7-1.
That was more than enough for Rangers starter Tommy Hunter, who improved to 4-0 by holding the Astros to five singles and one run in six innings. He got a big double play in the third after singles by Jason Castro and Oswaldo Navarro to open the inning.
"Hunter threw a good game," Mills said. "He's done a good job a lot this season, so that wasn't as surprising as Roy struggling like he did. He doesn't struggle like that. He's been outstanding and thrown the ball the well."
Houston continues its 10-game road trip Monday in Milwaukee, where right-hander Bud Norris makes his return to the mound after more than a month on the 15-day disabled list.
"Glad to be back in the National League," Mills said. "We're excited to see Bud come back off the disabled list and throw the ball well like he did in his rehab starts. That's definitely something we're really looking forward to."