(Sports Network) - According to the current depth chart on Arizona's website, future Hall of Fame pitcher Randy Johnson is fifth in the rotation. Usually the arms in that slot are the weakest of the bunch, but in this case, the Diamondbacks have a revived ace up their sleeve.

The fifth spot was perhaps a perfect distinction for Johnson from late May to July 1, when the lanky left-hander went 0-6 in eight starts -- all Arizona losses. But since then, however, Johnson is back to his old mullet days in Seattle and scowling at batters even if they strike out. I always thought that was weird when he did that.

Johnson is 3-0 with a 2.33 earned run average since then, including a solid showing against the very familiar Chicago Cubs on Monday. The Big Unit chucked seven shutout innings of two-hit ball to improve to 13-0 with a microscopic 1.84 ERA in 14 career games versus the Cubs. Johnson is only the second pitcher to ever go at least 10-0 against the Cubs, and the other was Sal Maglie, who went 10-0 in 19 starts versus Chicago (1954-1958). Johnson threw just 86 pitches against Chicago to even his 2008 record at 7-7 through 18 trips to the hill. He is also just nine wins shy of 300 for his career.

With the Diamondbacks struggling as of late, now couldn't be a better time for manager Bob Melvin to get his veteran southpaw nice and loose. Arizona is just one game ahead of the Dodgers in the National League West standings, and will need Johnson's best stuff on the upcoming 10-game road trip against division foes San Francisco, San Diego and Los Angeles.

The 44-year-old and near seven-footer (6-foot-10) is sixth in baseball history among left-handers with 291 career victories, and the active leader in strikeouts with 4,715. He is second to Nolan Ryan in that category, as Ryan ended his brilliant career with an amazing 5,714 K's from 1966-1993. Johnson is the only player in major league history to have 2,000 strikeouts with two different ballclubs, having fanned 2,162 batters with the Mariners before posting 2,003 K's as a Diamondback. He is also just one of four pitchers in history with 4,000-plus strikeouts (Ryan, Roger Clemens, Steve Carlton).

Johnson is going to keep on piling up K's if he continues to pitch at a high level, but let's not forget this man is no spring chicken. Johnson can still crank his fastball up to the mid-90s, though his health will always be a concern. It seems that his chronicled back issues have taken a back seat for now, something Melvin I'm sure keeps in mind. Johnson's next scheduled start isn't until Sunday against the Giants at AT&T Park, and he has posted two no-decisions -- both Arizona losses -- in the 2008 series with San Francisco. In 22 career starts against the Giants, he is 7-8 with a 3.38 ERA.

RAUCH MAKES IMMEDIATE IMPRESSION

It didn't take long for newly-acquired relief pitcher Jon Rauch to make an impression with his new ballclub. Arizona obtained the services of the right- hander on Tuesday from the Washington Nationals in exchange for second baseman Emilio Bonifa.

Rauch compiled a 4-2 record and 2.98 ERA for the Nationals this year, while converting 17 of his 22 save opportunities. He made his Arizona debut in Tuesday's 9-2 victory over the Cubs, as he allowed one hit with a pair of strikeouts in just an inning of work.

The righty was pleased to be a member of the Diamondbacks, alluding to how this team is currently on top of its respective division. Rauch will definitely be relied on this season with the D'Backs going to battle with a beleaguered and banged-up bullpen. Rauch is slated to be the setup man for closer Brandon Lyon.

Rauch was second in the big leagues with 85 appearances in 2006 and led the majors with 88 last season.

In other moves for Arizona, prospect Jamie D'Antona had his contract selected by the ballclub after dealing for Rauch. D'Antona was drafted in the second round of the 2003 First Year Player Draft.

"There's a guy that deserves a shot at the big leagues," Melvin said. "You look at his Triple-A numbers and they're off the charts. Through hard work and great performance, he deserves a shot at the big league level."

The D'Backs made room for D'Antona on the roster by switching injured outfielder Eric Byrnes from the 15-day disabled list to the 60-day DL. Also, relief pitcher Connor Robertson was optioned back to Triple-A Tucson.

WHO'S HOT

Besides Johnson, Diamondbacks shortstop Stephen Drew is currently riding a nine-game hitting streak. He is batting .395 over that stretch (17-for-43) with six runs batted in, three doubles and a pair of triples.

WHO'S NOT

Arizona has lost two straight and five of ace Brandon Webb's last eight starts, with the right-hander going 2-2 with a 4.10 earned run average over that stretch.

ON DECK

If the Diamondbacks want to maintain their edge on the NL West standings, they must complete a three-game sweep of the Chicago Cubs in the finale on Wednesday.

After hosting the Cubs in the final test of a six-game homestand, Arizona will embark on a 10-game road trip against the Giants, Padres and Dodgers.