The Arizona Dimaondbacks bolstered their bullpen Tuesday, acquiring Nationals closer Jon Rauch for infield prospect Emillio Bonifacio.

At 6-11, the 29-year old is the tallest pitcher in major league history, surpassing his new teammate Randy Johnson by an inch. So far this season, he has 4-2 record with a 2.98 ERA and 17 saves in 48 apperances for the Nationals.

Current Diamondbacks closer Brandon Lyon has been inconsistent at times this year, as he has blown five of his 25 appearances and has an ERA just under 4. This past Sunday, he gave up five runs to the Dogers in the ninth inning, as they rallied to beat Lyon and the Dbacks 6-5.

Prior to the start of the season, the Nationals re-signed Rauch to a two-year, $3.2 million dollar contract with a club option for 2010.

Jon Rauch is a proven late-game reliever who we control through 2010,” Arizona general manager Josh Byrnes said. “We are pleased to add him as we attempt to defend our division title.

Despite being one game under .500, the Diamondbacks (49-50) are tied with the Dodgers for first place in the weak National League West.

Rauch had been with the Nationals since he was acquired from the Chicago White Sox on July 18, 2004 when the club was the Montreal Expos. He has appeared in 255 career games, posting a 24-17 record with a 3.63 ERA and 37 saves over parts of seasons.

Bonifacio, 23, appeared in only eight games this season for the Diamondbacks after being recalled on July 4, and batted .167 (2-for-12) with two RBI. He spent most of the season at Class AAA Tucson, where he hit .302 (111-for-367) with a home run, 29 RBI and 17 stolen bases.

Bonifacio earned a spot on the Pacific Coast League All-Star squad and also was a member of the World Team in the Baseball Futures Game. A leadoff hitter and recognized as one of the fastest runners in professional baseball, Bonifacio led the Southern League in stolen bases (41) and hits (157) last year.

“This trade brings us a quality, young player, who has the potential to develop into a solid leadoff hitter and outstanding defensive second baseman,” Nationals general manager Jim Bowden said. “He is a high-energy player with a lot of potential, and we anticipate he’ll fit nicely into our long-term plan of drafting, acquiring and developing a solid nucleus that will lead our club in the near future.”

Bonifacio joins third baseman Ryan Zimmerman, outfielders Elijah Dukes and Lastings Milledge, and catcher Jesus Flores as Nationals who began this season 23 years old or younger. Bonifacio, Dukes, and Milledge all were acquired via trade within the last year.

After acquiring Bonifacio, the Nationals optioned him to Class AAA Columbus of the International League and recalled right-hander Garrett Mock from Columbus. Mock went 6-3 with a 3.05 ERA in 17 starts with the Clippers.