PHOENIX -- An MRI on the jammed left thumb of D-backs outfielder Justin Upton on Tuesday afternoon showed a bone bruise, and the All-Star is unsure if the injury will land him on the 15-day disabled list.Upton, who was evaluated by hand specialist Dr. Don Sheridan and had fluid drained from his thumb, is listed as day to day. "I just don't know," Upton said after Tuesday's 5-4 loss to the Pirates. "I'm going to come in tomorrow and see how it feels. You have to give it a little bit of time. Right now, I'd like to make sure it's right -- where I can swing the bat again." Upton jammed his thumb while sliding into second base to break up a double play in the seventh inning against the Giants on April 8 and has not been the same since. He went 2-for-6 with a double, two walks, and two runs scored before jamming his thumb, and he's gone 5-for-24 since. "It's been nagging me for a little bit. You have to take it day by day," Upton said. "We really wanted to know what was going on in there, so we had the MRI. Everything came out pretty positive." Upton has not hit a home run or driven in a run this season. "It doesn't seem like [Upton] will be 15 days, but it's not going to be tomorrow either," D-backs manager Kirk Gibson said. "We're are going to have to play short, and some guys are going to have to step up." Chris Young, who suffered a right shoulder contusion after making a leaping catch and slamming into the wall in left-center field in the fourth inning on Tuesday, is also listed as day to day. The D-backs will also be without Geoff Blum, who was placed on the disabled list after pulling a side muscle during batting practice, Gibson announced after the game. The club will promote A.J. Pollack from Triple-A Reno to add depth in the outfield, the manager said. "There are a lot of things that might happen," Gibson said. "It all happened very quickly for us. We'll have contingency plans available with the best of what we can do. We are somewhat in a holding pattern with a couple of guys."