When navigating through the rigors of a 162-game major league season, injuries happen, it's good to have options on your bench that can come in and do the job when called upon.

One of the reasons why the Arizona Diamondbacks were the pick of many pundits to repeat as National League West champs was their depth - especially in the outfield.

Just 11 games into the season, that depth is being tested. Right fielder Justin Upton was out of the lineup in Tuesday's 5-4 loss to the Pittsburgh Pirates, and saw a hand specialist about his dinged-up thumb.

And Chris Young, off to a blazing hot start, left Tuesday's game in the 4th inning after robbing Pittsburgh's Pedro Alvarez of extra bases with a catch that carried him right into the center field wall. Young was diagnosed with a right shoulder contusion.

The Diamondbacks finished with Willie Bloomquist in left field, Gerardo Parra in center and Jason Kubel in right.

According to manager Kirk Gibson, the Diamondbacks will call up outfielder A.J. Pollock from Triple-A Reno Wednesday, but not to replace Young or Upton. Pollock will slide into the roster spot held by veteran Geoff Blum, who was injured in warm-ups Tuesday.

Pollock was hitting .340 in 12 games for the Aces so far this season.

Gibson listed both Young and Upton as "day-to-day". Upton had fluid drained from his left thumb Tuesday, and is trying to avoid a stint on the disabled list.

"I hope so. I just had it done today so I really don't know," Upton said. "I'm going to come in (Wednesday) and see how it feels and come in the next day and see how it feels. It's one of those things that you have to give a little bit of time, but right now it doesn't look like we have the time."

Young is scheduled to have an MRI Wednesday to further explore the shoulder, which showed no structural damage in x-rays taken Tuesday night.

"The frustration level is real high," Young said. "It's just bad timing, I guess any time you get hurt it's bad timing - especially with some guys down right now you want to be out there to help the team and do what you can."

Gibson was in full planning mode immediately following the game, but several roster scenarios are up in the air as the club waits for full diagnosis on its two stars.

"It doesn't seem like (Upton) will be 15 days, but it's not going to be tomorrow, either," he said. "We're going to have to play short and some guys are going to have to step up."

Arizona Sports' Kyndra de St. Aubin and Charlie Feinerman contributed to this report