The Philadelphia Phillies acquired closer Carlos Estevez from the Los Angeles Angels on Saturday, paying a heavy price in two top pitching prospects but adding a dynamic arm to an already strong bullpen.

The deal for the 31-year-old Estevez, who is a free agent this winter, will send right-hander George Klassen and left-hander Samuel Aldegheri to the Angels.

In Estevez, the Phillies add an established late-inning reliever to a bullpen rich with pedigree. In addition to All-Stars Jeff Hoffman and Matt Strahm, the Phillies have 23-year-old Orion Kerkering as well as left-handers Jose Alvarado and Gregory Soto, both of whom have closing experience.

Estevez has displayed immaculate control this season, with only three unintentional walks in 34 innings. He has struck out 32 and limited hitters to a .169/.202/.288 slash line while posting a 2.38 ERA with 20 saves.

"He's one of the best relievers in baseball this past year," Phillies team president Dave Dombrowski said. "He's a guy that can pitch the ninth inning. How [manager Rob Thomson] determines how he's going to use him, we'll see. It wouldn't surprise me if he gets a lot of ninth innings."

At 64-39, the Phillies have the best record in baseball and are widely regarded as the World Series favorite. Dealing prospects the quality of Klassen and Aldegheri for an impending free agent reliever is a heavy price but one that reflects the team's urgency after back-to-back losses in the World Series and National League Championship Series.

"We are trying to win," Dombrowski said. "We think he's a guy that can be a real significant piece of that."

Klassen, 22, is the prize of the deal. A sixth-round pick last year out of Minnesota, he struggled to throw strikes in college but has turned into a revelation with the Phillies. Featuring a 100 mph-plus fastball, he made nine starts in Low-A and posted a 0.71 ERA with 57 strikeouts and 12 walks in 38 innings. Since his promotion to High-A, Klassen has a 4.22 ERA but has maintained his high strikeout rate and kept walks under control.

He could move fast in a depleted Angels farm system, though Aldegheri is closer to the big leagues. The 22-year-old, born and raised in Verona, Italy, recently was promoted to Double-A after carving through High-A with 95 strikeouts, 28 walks and only three home runs allowed in 68 innings.

"We didn't want to give them up," Dombrowski said, "but it's sort of the price of acquisitions at this time."