PHOENIX -- Gerardo Parra is slated to make his second start of the season in right field on Tuesday and could see more action at the position if Justin Upton misses more time because of his jammed left thumb.

Parra, the club's fourth outfielder, is hitting .316 in 18 at-bats this season. He's appeared in the first 10 games this season, including three starts in left field. Parra, who won a Gold Glove last season, made 117 starts in left field, six in right field and one start in center in 2011.

Jason Kubel, acquired during the offseason, has started seven of the club's first 10 games in left field this season. Upton was not in Tuesday's lineup against the Pirates and visited hand specialist Dr. Don Sheridan.

"I've doing great, and I think I'm taking advantage of the opportunities they are giving me," Parra said. "Coming in late in the game is not easy. You have to really prepare to do it, but I'm preparing myself for the role."

Blum lands on disabled list

PHOENIX - Following Tuesday night's 5-4 loss to the Pirates, the D-backs placed Geoff Blum on the 15-day disabled list. The veteran pulled a side muscle during batting practice.

Gibson said the club will promote outfielder A.J. Pollock from Triple-A Reno to take his place on the roster.

Through 12 games with the Aces this season, the 24-year-old is batting .340 with six runs scored and five RBIs.

Pollock hit .315 in 54 at-bats with the D-backs during Spring Training.

In limited work this season, Blum had one hit in 11 at-bats.

D-backs finding success in first inning

PHOENIX -- The D-backs aren't wasting any time warming up their bats this season.

Through 10 games this season, the D-backs have scored in the first inning eight times for 14 total runs. Aaron Hill's first-inning homer on Monday against the Pirates marked the fifth long ball the team has hit in the frame in 2012.

Last year the team averaged 0.57 runs in the first, but two weeks into this season, that number has ballooned to 1.40.

"I like it. The guys have been great," manager Kirk Gibson said. "When I came in here last year, one of the things we talked about was preparation and being ready for the very first pitch. As far as where we were last year, we are light years ahead."

Setting the table for such productive starts have been guys like Willie Bloomquist, Ryan Roberts and Hill at the top of the order.

When the D-backs score in the first inning, the trio is a combined 5-for-10 with six runs scored, two RBIs and two homers.

Chris Young has benefited the most from his teammates getting on base early. He has six RBIs on four hits and three homers in the first inning this year.

"Those guys are getting things started for us," Young said. "Anytime you get on base and cause havoc like those guys do, it puts a lot of pressure on pitchers. We have a good lineup that knocks them in, too."

The D-backs' rotation doesn't mind the first-inning production, either. With so much run support, the starters aren't feeling as much pressure when they're on the mound.

"We've had a lot of opportunities in the first inning," Joe Saunders said. "We played long ball [Monday], and it's always nice when you can get the easy ones."

Saito nearing rehab assignment

PHOENIX -- D-backs reliever Takashi Saito practiced covering first base on Tuesday, and the club will wait to see how his injured calf responds before sending him on a rehab assignment.

"There's nothing concrete with him now," D-backs manager Kirk Gibson said. "I feel his arm is fine, but when he feels like he's ready to go, I'd probably ask him if he'd go down somewhere in the Minor League system to pitch a time or two and see how he covers the bases."

The club doesn't want Saito to jump straight from controlled drills to live action in the big leagues. The pitcher has been running in the therapeutic pool at Salt River Fields, and Gibson said a gradual approach back will help Saito stay healthy throughout the season.

"I want to make sure he's ready to contribute and sustain what he's going to be up against," Gibson said. "This game here is pretty quick and there's a lot at stake. I'd say you go full speed more than once. It's not going to do any good if I get [Saito] back for a week, and [then be] back in this position."

Before sustaining the injury in Spring Training, the D-backs pegged Saito for the seventh-inning role to set up David Hernandez and J.J. Putz.

"We signed him because we know what he's capable of doing," Gibson said. "We want to put him in a position to do that consistently. I don't want him short term, I want him long term, that's my goal."