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The Los Angeles Angels made a move to keep up with the Texas Rangers in the AL West by trading for infielder Alberto Callaspo last week.

The next step was to add a quality pitcher, one who could counter the Rangers acquiring former Cy Young winner Cliff Lee.

A three-time All-Star who's one of the most durable pitchers in baseball should do the trick.

The Angels bolstered their already-solid rotation by acquiring right-hander Dan Haren from the Diamondbacks on Sunday in a deal that sent left-hander Joe Saunders and three other players to Arizona.

The last-place Diamondbacks also get right-hander Rafael Rodriguez, left-hander Patrick Corbin and a player to be named in the deal.

"We really felt good about our starting five moving forward with what we had but this is a huge opportunity for us to upgrade not only now but for the next several years," Angels manager Mike Scioscia said. "This guy still has his stuff and it gives us a deeper front end of our rotation, and that's what every championship-caliber team is really striving to do. We were able to do that with this move and we're excited about it."

One of the most prized pitchers available as the July 31 non-waiver trade deadline approaches, Haren was the type of pitcher the Angels had been after since Texas traded for Lee in a July 9 deal that sent rookie first baseman Justin Smoak and a package of prospects to Seattle.

Los Angeles has a rotation that's strong up front with Ervin Santana, Jered Weaver and Joel Piniero, but is missing injured left-hander Scott Kazmir.

A three-time All-Star, Haren has averaged 15 wins over the past five seasons and is 7-8 with a 4.60 ERA in 21 starts this year. In his sixth season, the 29-year-old was tied for the NL lead with 141 strikeouts through Saturday's games.

"A top-of-the-rotation guy that's going to help us not just this year but years down the road," Angels general manager Tony Reagins said in Texas before his team played the Rangers. "The addition of Dan gives us five guys that are really talented."

The trade ends a long ordeal for Haren.

In the second season of a four-year, $44.75 million contract, Haren had been rumored to be headed to three or four different teams. Now, he can relax, headed to a winning team and back to Los Angeles, where he grew up and still has family.

"At this point, being on the West Coast has a lot of value to me, being near my family and going to a ballclub that is dedicated to winning," Haren said after Arizona's game against San Francisco. "I am very excited for the opportunity. I am sad to go from here, all the guys and I had a good time here but I am really excited about going there and having a chance to win."

Haren might not make his Angels' debut right away, though. Scioscia was still evaluating the rotation and where to slip the right-hander in. After playing the Rangers, Los Angeles heads home to face the Boston Red Sox.

"I believe his turn would be tomorrow, but we're going to evaluate a couple of things and get a chance to talk to him and see where he is," the manager said. "We've got guys who are on regular turn now, so we do have the luxury of folding him in somewhere or putting him out there to pitch tomorrow."

Saunders was an All-Star in 2008 and had a 54-32 record and 4.29 ERA in 115 games over six seasons with the Angels. He was 6-10 with a 4.62 ERA in 20 starts for Los Angeles this year, his eighth in the organization.

"I've been in trade talks in the offseason and stuff like that but you never really think it's going to happen," said Saunders, who lives in Arizona. "They obviously think highly of me, so it will be a new challenge."

Rodriguez appeared in one game this season, allowing a run and a hit in two innings, and was 0-1 with a 5.58 ERA in 18 relief appearances over five stints with the big league club last year.

Corbin, a 21-year-old left-hander, has spent the season in the lower levels of Los Angeles' system.

With a starter and two solid prospects, the Diamondbacks found the right match for dealing Haren.

"(Saunders) brings an element to our club that I think we need," Arizona interim GM Jerry Dipoto said. "The prospects in the deal bring us talent that we need to build with. Therefore, I felt that this deal checked a lot of boxes for the Arizona Diamondbacks."