There had been no indication that the finger was a lingering issue until Hale brought it up prior to Thursday's game.
"I think his finger is still not where we'd like it to be after hitting it on the ground in San Diego," Hale said. "He's still having some residual effects of that with feel. He's been good to pitch. He's pitched through it. But we've got to make 100 percent sure that thing is not affecting his performance."
The D-backs gave up a lot for Miller in a December deal with the Braves and were counting on him to be the team's No. 2 starter behind ace Zack Greinke.
Miller is under team control for two more seasons after this year, so the D-backs are trying to take the long view when it comes to the 25-year-old.
"Health is No. 1, and No. 2, we have to find a way to get him back to where he was last year," Hale said. "It's not about his next start or three starts from now, it's about this long time that we have him. That's what we've been trying to tell people, even before the season. It's not a one-year wonder, it's three years of him, and we want him to be the No. 2 guy behind Zack."
As to whether Miller will make his start Sunday, Hale said, "If we feel like he's healthy enough to go out there on Sunday, then we'll let him go."
Regardless of whether Miller is healthy, it sounds like the D-backs will do some shuffling of their roster this weekend.
Right-hander Josh Collmenter is set to return from the disabled list, and the team could decide to go from 13 pitchers to 12 by adding a position player.
The bullpen, which has struggled of late, will be evaluated as well.
"We need to look at each one of our bullpen members," Hale said. "We'll get back to Phoenix and see [GM Dave Stewart] and talk honestly about our bullpen. Do we need to make some changes? There are some guys underperforming, and [do they] need to be sent out to get their game back. It's going to be an interesting weekend."