D-Backs notebook: Dunn producing, taking pressure off rest of lineup

HOUSTON - Adam Dunn’s numbers are enough to suggest he has made an immediate impact in his first week with the Diamondbacks — a .333 batting average, a .520 on-base percentage. His presence in the cleanup spot has meant just as much, manager Bob Melvin said.

Bats stay hot as D-Backs slam Astros

Inside Baseball: This Steinbrenner also plans to spend, spend, spend

Read Jack Magruder's blog, 'Inside Baseball'

“He takes a lot of pressure off everybody in the lineup,” Melvin said.

“We’re deeper, and it’s made our lineup tougher to navigate. He hasn’t hit multiple home runs, but that’s coming.”

Dunn has hit safely in all five of his games with the D-Backs and has walked seven times.

He was in the middle of three big innings recently, getting a two-run single in a five-run fifth at Colorado on Thursday, walking in a three-run first at Houston on Friday before singling in a five-run first Saturday.

“He has a terrific eye. Even when he is not hitting, he’s on base,” Melvin said.

“Those things are very impactful. He makes everybody a better hitter with his presence.”

PETIT COMES UP BIG

Yusmeiro Petit had not pitched for eight days, although it hardly showed.

Petit, commanding his pitches and keeping them low in the strike zone, threw seven innings for the first time this season, giving up two runs on four hits while striking out five.

“I know it’s been a long time, but I was still throwing my bullpens, still staying sharp,” said Petit, 2-3 with a 3.02 ERA, through interpreter Miguel Montero. “I was able to make good pitches, relax and throw strikes. That run support in the first inning was good. I didn’t have to try to do too much.”

Petit, who last started Aug. 7, has stepped into the role occupied by Edgar Gonzalez at times this season and last, as a man capable of starting on an irregular basis and still responding.

“He quietly goes out there and goes about his business,” Melvin said. “You can mix up his roles, which isn’t easy to do, and he can handle it.”

JACKSON TO REST

Left fielder Conor Jackson will get a day off today, Melvin said, although it has nothing to do with his health despite the fact he collided with the metal left-field scoreboard in the seventh inning chasing Ty Wigginton’s double and got hit by a pitch in the right leg in the eighth.

“I’m pressing a little bit right now,” said Jackson, 3-for-21 on the road trip.

“It seems like nothing is falling in for me. That’s the game of baseball. You go through tough streaks. If I get a day, it’s more of a mental day.”

Jackson has played every day since June 7, starting all but one, and playing most after getting extra pregame work in left field, where he moved for good July 9.

SHORT HOPS

Chris Burke started for the third straight game at second base against an opposing left-hander, and with a single and a walk Saturday is 4-for-12 with two home runs and four RBIs in those games.

Augie Ojeda is likely to start against Houston right-hander Roy Oswalt today.

Jarrod Parker, the D-Backs’ first-round pick in the 2008 draft, threw five shutout innings for Class A South Bend on Saturday, improving to 11-5 with a 3.48 ERA.

Parker is 5-0 with a 2.25 ERA in his last seven starts, striking out 41 in 40 innings.