The Arizona Diamondbacks improved their chances of winning the National League West on Monday, working out a waivers deal with the Cincinnati Reds for slugging outfielder Adam Dunn in exchange for three prospects.

Dunn will be a huge upgrade for Arizona, which has struggled to score runs since its tremendous stretch during April. The Diamondbacks currently have a one-game lead over the Los Angeles Dodgers in the division, sitting with a 60-58 record. They have gotten to this point, though, by relying on excellent pitching at the front of the starting rotation.

Brandon Webb has led the way, going 17-4 with a 2.88 ERA and 139-to-41 K/W ratio. Webb is currently atop league leaders in nearly every statistical pitching category, using his tremendous sinker to consistently put up zeros on the scoreboard. As of this writing, he appears to be the easy favorite to win his second Cy Young Award in three seasons.

Dan Haren, acquired from the Oakland Athletics in a deal this offseason, has been tremendous in his own right, perhaps becoming ace 1A to Webb. Haren has made a solid adjustment to the senior circuit—as many predicted—and is currently fourth in the NL with 147 strikeouts and eighth with a 3.00 ERA.

Randy Johnson has flashed glimpses of dominance as well, especially considering that he has now had to overcome two back surgeries after his 40th birthday. Johnson has struck out nearly a batter per inning, registering a 114-to-29 K/W ratio in 21 starts. While the 44-year-old left-hander is no longer the same pitcher as he was during his prime, he has pitched much better than his 9-8 record indicates.

While Micah Owings and some other Arizona starters have struggled at times, the Arizona staff currently ranks first in the circuit in quality starts (70), WHIP (1.27), second in opponents’ OPS (.706) and fifth in ERA (3.96).

The Diamondbacks’ offense, on the other hand, has really had some difficulties plating runs since the middle of May.

Orlando Hudson, Connor Jackson and Mark Reynolds have put together strong campaigns to provide a few bright spots.

Hudson, one of the leaders in the clubhouse, has posted a line of .305/.367/.450 while playing his usual excellent defense at second base. However, he recently dislocated a bone in his left wrist recently, forcing him to undergo season-ending surgery and perhaps prompt Arizona to seriously go after Dunn.

Jackson has been the most consistent performer, batting .311/.390/.487 while producing the highest OPS on the roster.

Reynolds has provided some pop in the middle of the line up as well—24 home runs and 74 RBIs—but is still only batting .246/.324/.491.

The real story, however, lies in the performance in the Diamondbacks’ talented trio under the age of 25, shortstop Stephen Drew and outfielders Justin Upton and Chris Young. The group has truly struggled at times as pitchers have learned to exploit their weaknesses more effectively.

Drew is hitting .280 and is third on the team with 14 homers, but his on-base skills (.319 OBP) have yet to fully develop to an acceptable level.

Ditto for Young, whose line of .232/.296/.416 leaves a lot to be desired. He is a tremendous athlete with plus power, but is among league leaders in outs made.

Injuries have dragged down Upton, who is batting .242/.353/.433 with 11 home runs in 83 games. He still has the upside of the group and projects as a future MVP candidate, as he is a rare five-tool talent.

The growing pains for this group, however, have played a major factor in the tailspin in Phoenix.

Then there is the situation involving popular left fielder Eric Byrnes, who was rewarded with a hefty contract this offseason but struggled offensively before sustaining a season-ending injury. Byrnes is frequently labeled as “the heart and soul of the team,” but the decision to offer him such a lucrative deal looks like a major mistake. It is certainly easy to Monday morning quarterback this all day, but one-time top prospect Carlos Quentin was a more cost-effective option internally. Instead of giving Quentin a shot, though, the team agreed to give the veteran $30-million over three years. Going by how year one has turned out, it is not too difficult to come up with a lot of better ways to invest $10-million.

With the combination of several disappointing individual performances from the young position players and injuries—all while Quentin has flourished into the front-runner for MVP in the American League for the Chicago White Sox—Arizona quickly floundered its early lead in the division. The major reason has clearly been the offensive unit overall, as the D’Backs rank in the middle of the pack in several of the most important statistical batting categories—including 10th in runs scored and 11th in on-base percentage and OPS.

Luckily, strong starting pitching and the woes of nearly every team in the West have enabled them to stay afloat.

Which is why the addition of Dunn—albeit as a seven-week rental—will help a lot, especially with the loss of Hudson and the failed pursuit to acquire Mark Teixeira in July. As polarizing as a player as he is, he adds some much-needed on-base skills and power to a run-starved lineup. A Three True Outcome Player, he is tied for the majors’ lead with 32 home runs and his .901 OPS is good for 15th in his league. His low batting average, high strikeout totals and poor defense in the outfield turn off many traditionalists. Still, he flat-out produces at the plate, using his excellent on-base skills to keep rallies going and tremendous power to add a presence to any lineup. While he is undervalued by traditionalists and overvalued by some statistical analysts, he will hit his homers and draw his walks, two areas of concern for Arizona to this point.

The addition of Tony Clark will also help. Clark is a great influence on the youngsters, is a solid left-handed bat off the bench and was one of the Diamondbacks’ team leaders when they made the playoffs in 2007.

Still, though, Dunn has a chance to make a real difference. Considering the alternatives, he gives his new team a much better chance of holding off the Dodgers, who beefed up their offense by adding Manny Ramirez at the trade deadline.

The Dodgers are going for it right now, evident by their decision to part with so many prospects in exchange for third baseman Casey Blake and Ramirez. While they are viewed as the favorite by many and have the better run differential, though, do not count out the Diamondbacks. The addition of a bona-fide slugger, as much as he drives some scouts crazy, will certainly help them finish what was started in the season’s first month. If he can really get hot and #### out some big homers, as he did earlier this summer, look out.

Reds’ Side: On the Reds’ side, they acquired minor league pitcher Dallas Buck and two prospects to be named later. Buck, a former collegiate All-American who helped push Oregon State to the College World Series, recently began throwing again earlier this summer after undergoing Tommy John surgery in 2007. The former third-round pick has excellent stuff when healthy, but has a long way to go. He has made some progress since returning, posting a 3.55 ERA and 28-to-11 K/W ratio in 50.2 innings pitched combined between the Midwest and California League. He will report to the Florida State League to pitch for the Sarasota Reds.

The Reds could have waited to cash in on a pair of compensation picks when Dunn bolted for free agency. Instead, they now will get three prospects instead of two. While I do wonder if they could have received better value if a deal was reached before the trade deadline—after all, it is going to be tough to place that 40-homer, 100-walk production—it is still too early to tell how well they did until the other prospects are announced.

Plus, Arizona is only getting seven weeks of Dunn, making this deal seam reasonable for both parties. Cincinnati was not going to playing any meaningful games either way. So, while this ultimately means that Corey Patterson and his rather embarrassing line of .189/.221/.328 will get more playing time in the short term, this is a step in the right direction for the Reds in the long term. They have a strong young core, and parting with Dunn and Ken Griffey Jr. signals a new era at Great American Ballpark. Walt Jocketty also got designated for assignment veteran catcher David Ross, who was—like many other soon-to-be free agents in the organization—dead weight.