ARLINGTON -- A few hours before the start of a crucial four-game series with the front-running Rangers in the American League West, the three-time reigning division champion Angels moved to bolster their offense on Thursday.


Alberto Callaspo, a switch-hitting infielder expected to spend most of his time at third base, was acquired from the Royals in exchange for pitchers Sean O'Sullivan and Will Smith.

Callaspo, 27, is hitting .275 for the Royals this season after batting .300 in 2009 with a career-high 11 homers and 73 RBIs. He has eight homers and 43 RBIs this season. He signed with the Angels in 2001 as a teen in Maracay, Venezuela, and was traded to Arizona for pitcher Jason Bulger. The Royals acquired Callaspo for Billy Buckner.

"He'll be a boost," Angels manager Mike Scioscia said. "He can definitely play third base every day. We'll see how some of the pieces fit. The work he does in the batter's box is special. He can hit. He'll help fill the void Kendry Morales' departure created."

O'Sullivan, 22, held the Yankees to two runs on two hits in six innings in a victory on Tuesday night at Yankee Stadium. The Angels were 9-2 in the big right-hander's 11 starts over the past two seasons. The San Diegan was a third-round pick in the 2005 First-Year Player Draft.

Smith, a 21-year-old native of Georgia taken in the seventh round of the 2007 First-Year Player Draft, is a 6-foot-5 left-hander in his third professional season. He has pitched for high Class A Rancho Cucamonga and Double-A Arkansas this season and is considered to have high upside.

"This was not by any means an easy decision on Tony's part," Scioscia said, referring to general manager Tony Reagins. "It's not easy to put Sean O'Sullivan or Will Smith in a deal unless we were getting a player who can help us."

Callaspo is expected to join the Angels on Friday night. O'Sullivan, who had been scheduled to pitch Sunday's series finale, likely will give way now to Trevor Bell. Scott Kazmir (shoulder fatigue) is not eligible to come off the 15-day disabled list until Monday, and it is unclear when he'll be ready to rejoin the rotation.

"It's weird," O'Sullivan said, minutes after being informed of the deal by Scioscia. "It's the first time I've ever been traded. The goal is to go to a place where they need you, want you, so you can show you're capable of playing at this level.

"I'm trading red for blue. That's all I know right now."

Callaspo, who will be under club control for three more years, is arbitration-eligible this winter and figures to get a substantial raise from the $460,000 he is making this season, into the $2 million range.

"I think over the long haul, it's going to have an impact, a guy who can hit the ball and put the ball in play," Scioscia said. "Alberto is a good offensive player. He can hit in the two hole, the six, seven holes with guys in scoring position.

"We were looking for offense. He can play a variety of positions, let you move some guys around. This is one move that we think is a good move for a number of reasons."

Callaspo is familiar with the Angels' aggressive style and personnel -- especially shortstop Erick Aybar. They were teammates coming up through the system, Callaspo playing second base for the most part.

"Alberto's been a terrific player for us, very consistent, and he was able to solidify himself as a very productive Major League player here," Royals general manager Dayton Moore said.

"We just got an opportunity to get a quality young pitcher in O'Sullivan that we like. He's got the toughness, the competitiveness and the ability to pitch with command of the fastball. It was just the right time for us to make a move."

Moore said the injuries that have put starters Gil Meche and Luke Hochevar on the disabled list and that knocked out fill-in Anthony Lerew were not the motive for the deal.

"We've got the long-term in mind," Moore said.