"We're kind of weighing and debating back and forth in the room what's our best roster," Hale said. "That one spot has really been a great battle. You talk about the middle infield -- that last reliever spot might be a better battle than that."
• Offseason conditioning paying off for Tomas
The competition could become even more wide open if Hale decides to carry 13 pitchers instead of the expected 12, something the manager said is an increasing possibility. The D-backs have just one off-day in April, which could prove taxing to the bullpen.
Hale said Marshall, who allowed four runs in the ninth inning of Friday's 7-5 win over the Indians, has "no ill-effects" facing live hitters thus far this spring. Marshall was struck by a line drive while pitching in Triple-A Reno last August, fracturing his skull in the process.
Fabian Ardaya is a correspondent for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.