Baseball DIAMONDBACKS NOTEBOOK

PHOENIX — The Chicago Cubs are coming.

That means large, rowdy crowds at Chase Field. It also means the Arizona Diamondbacks will try to maintain their four-month stay atop the NL West against a World Series favorite.

The Cubs boast an NL-best 58-40 record after throttling the Houston Astros 9-0 on Sunday.

"Right now we know every game is an important game," Arizona closer Brandon Lyon said. "They're a hot team."

Randy Johnson will take the mound today against Rich Harden (5-1, 2.19 ERA), who will make his second start with the Cubs since they acquired him from Oakland. The D-backs will also face Jason Marquis (6-5, 4.44) and lefty Ted Lilly (9-6, 4.49).

"I think we miss a couple of their big pitchers, which would be nice," said Brandon Webb, who allowed a run in eight innings Sunday for a no-decision in Arizona's 6-5 loss to the Dodgers. "It's going to be another big series."

The D-backs avoid Carlos Zambrano (10-4, 2.98) and Ryan Dempster (10-4, 3.25).

Chicago slugger Alfonso Soriano will miss at least part of the series; he begins a rehab assignment today in Peoria and might play against the Tucson Sidewinders on Tuesday.

In May, the Cubs swept the D-backs in three games at Wrigley Field. Snyder back Catcher Chris Snyder went 0 for 2 with a walk and sacrifice bunt in his return to the starting lineup. He was on the disabled list since July 1 for a testicular fracture after a foul ball hit him.

Snyder has been wearing a NuttyBuddy protective cup since the incident, and the change has reaped positive results. During a rehab stint on Friday, a foul tip hit Snyder.

"The NuttyBuddy did pay off," manager Bob Melvin said with a smile.

To make room for Snyder, the D-backs optioned catcher Robby Hammock to Triple-A Tucson for the second time this season.

"We haven't seen the last of Robby Hammock, whether it's September or another move we potentially have to make," Melvin said.

Clark also back

Two days after returning to the desert and his former club, Tony Clark got his first start with the D-backs. He replaced Chad Tracy at first base and went 0 for 4 with an RBI groundout and two strikeouts. He also committed an error.

Melvin said he wants to get Clark repetitions in the field. The 36-year-old played 70 games for San Diego before the Padres traded him on Friday — and just one of those games was a start in the field, on April 17.

"It's good to be back," Clark said.

Bullpen update

An MRI showed no structural damage in left-handed reliever Doug Slaten's strained right knee. The knee was drained and he will likely begin throwing after 3-5 days off, Melvin said. Slaten went on the disabled list on Saturday.

Chad Qualls, who has been sidelined with a tight back since Friday, would probably need another day off, Melvin said before Sunday's game.

Juan Cruz (oblique) threw 32 pitches in a bullpen and will likely throw another bullpen session before possibly going on a rehab stint.