The trade wheel of fortune kept spinning Thursday with veterans-for-prospects deals that typically dot the stretch run. More swaps were expected before Saturday's 4 p.m. deadline as pitchers Ted Lilly and Jake Westbrook could go.
The Philadelphia Phillies made the boldest move, getting Oswalt and about $11 million from the Houston Astros for pitcher J.A. Happ and two speedy minor leaguers.
"I'm excited," Phillies ace Roy Halladay said. "It says a lot that this team is dedicated to winning."
Oswalt agreed to waive his no-trade clause and approved the deal to the two-time defending NL champions. The three-time All-Star is set to start Friday night at Washington.
Still throwing hard at 32, Oswalt was 6-12 despite a 3.24 ERA for the foundering Astros. He asked for a trade earlier in the season and the St. Louis Cardinals were among the teams that were interested.
The Phillies took a seven-game winning streak into Thursday night's game against Arizona. They began the day 3½ games behind Atlanta in the NL East.
"We're still in first place right now, but we've got a long way to go," Braves pitcher Derek Lowe said. "They're definitely a better team with him, no doubt about it."
The NL West-leading San Diego Padres acquired infielder Miguel Tejada from Baltimore for a Double-A pitcher. At 36, the former AL MVP was hitting .269 with seven homers and 39 RBIs for the last-place Orioles, who earlier in the day hired Buck Showalter as their new manager.
"It's an honor to go to play where they want me. But I'm sad because I've loved being here," said Tejada, scratched from Baltimore's starting lineup for Thursday night's game at Kansas City. "I'm sad but I know this game is a business."
"It's a good chance at being in the playoffs and that's always good," Tejada added. "I think we can have a chance to win."
The AL West-leading Rangers added another bat for the playoff push, acquiring Cantu from the Florida Marlins for two minor league pitchers.
Cantu had two singles, scored twice and made an error in the Marlins' 5-0 win at San Francisco before being replaced on defense in the bottom of the eighth.
"Deep inside I'm very sad to leave the Marlins, of course," Cantu said. "My turn is to go right now to the Texas Rangers and help that ballclub out. They're playing well and winning the division. I think it will be fun. Whenever you go to a new team it's always fun and exciting. ... There's still two months to go. I know what I'm capable of doing."
Cantu is set to meet the team in Anaheim on Friday morning. He hit .262 with 10 home runs and 54 RBIs for Florida.
The Rangers already have All-Star Michael Young at third base - Cantu said in recent days he was prepared to switch back to his former spot at first base, a position of need for the Rangers.
"I had a good feeling something was going to happen," he said. "I really wanted to win here for the Marlins. It is a good relief because it was lingering around in my head for about a week. I tried not to think about it."
The Rangers sent Double-A right-handers Evan Reed and Omar Poveda to Florida. Texas also receives cash in the deal. The Orioles got right-hander Wynn Pelzer for Tejada.
The Phillies sent a pair of 19-year-olds, outfielder Anthony Gose and shortstop Jonathan Villar, to the Astros. Houston then traded Gose to Toronto for Triple-A first baseman Brett Wallace.