BOSTON -- Chad Qualls is out as the D-backs' closer, with Aaron Heilman getting the majority of save chances at least for the time being.

"I let Qualls know today that he won't close tonight, he probably won't close tomorrow night and we'll go from there," D-backs manager A.J. Hinch said prior to Arizona's game against Boston on Tuesday night. "I'm going to mix things up a little bit. I would say the majority of the opportunities will go to Heilman, but he might be needed in the seventh or eighth, too. We'll piece it together at the end the best we can, but right now, I'm going to take the guarantee of the back end away from Qualls and let him work things out in a different role."

What that role will be also has yet to be determined.

"I told him that it's not as though I can guarantee him a non-pressure situation to have him work on his delivery and have him work on his pitching motion," Hinch said. "So it might be the seventh or eighth inning, it might be when we're behind, it might be when we're ahead. I just told him to be ready to pitch."

Qualls has struggled throughout the season, compiling a 1-3 record and an 8.46 ERA in 28 games. The right-hander has blown four saves in 16 opportunities.

It seemed that Qualls had put things together when he had four straight scoreless outings from June 4-9. In that stretch, he did not allow a hit and picked up a win and three saves.

However, Qualls has lasted one-third of an inning in each of his past two outings and allowed seven runs (six earned).

Heilman, who was acquired from the Cubs during the offseason, has been the struggling bullpen's most consistent member this year, posting a 2.83 ERA in 29 games.

Over eight big league seasons, Heilman has 10 saves, with his season high being five back in 2005.

Hinch said the bullpen's other relievers would also need to step up their game.

"Guys like [Juan] Gutierez, [Esmerling] Vasquez, [Blaine] Boyer, [Carlos] Rosa, they're going to have to be thrust into maybe some uncomfortable situations just by need," Hinch said.