In a much-anticipated move, the Diamondbacks activated pitcher Doug Davis from the disabled list on Thursday. To make room on the roster, they designated reliever Brandon Medders for assignment.
The moves mean that Scherzer, who has a 2.33 ERA in four games (three starts), will head to the bullpen rather than Triple-A Tucson.
"That's our need right now, more in the bullpen than starting," Arizona manager Bob Melvin said. "Rather than sending him down to Triple-A and having him start, we feel there's more of a need for him here in this role."
Scherzer is likely to fill a variety of roles in the 'pen, pitching anywhere from the sixth to eighth innings depending on which Arizona relievers need a day off. Melvin said Scherzer could spell Juan Cruz in the sixth or Chad Qualls in the seventh. Should the D-backs' primary eighth-inning guy Tony Pena need a break, Melvin would likely slide Qualls to the eighth and use Scherzer in the seventh.
"We didn't want to just look at Scherzer as a long guy," Melvin said. "We feel he can be a significant piece there. We wanted to get Scherzer in what could potentially be a prominent role."
Scherzer retired the first 13 batters he faced in his Major League debut. He was then moved into a starting role where he pitched well. But with Davis set to come off the DL following April 10 surgery to remove a cancerous thyroid, someone had to be moved out of the rotation.
The move could also help the D-backs limit Scherzer's innings. The right-hander is in his first professional season.
"I know I can be a reliever or a starter," Scherzer said. "Just give me the ball. That's my mentality."
Melvin called Medders up to his hotel room around noon on Thursday to inform him of the decision. It was not an easy conversation.
"It's unfortunate that Med has to go," Melvin said. "It's not like he just has horrible numbers and needed to go. We just needed to make room and unfortunately it was his spot. I've got quite a fondness for Med. He's been here a few years with me and has done some good things for this team."
Medders was drafted by the D-backs in the eighth round of the 2001 First-Year Player Draft and had pitched in parts of four seasons at the big league level. He is out of Minor League options so the team has 10 days to trade, waive or release him.
In 18 appearances this year, Medders was 1-0 with a 4.58 ERA.
Steve Gilbert is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.