Is it the first of other moves to come? The D-backs' bullpen is 4-8 on the season with a Major League-worst 7.55 ERA. Relievers have blown seven saves in 14 opportunities.
"Maybe. I don't know what tomorrow brings," D-backs manager A.J. Hinch said. "I know what today brings: This is our team and we'll do our best to play winning baseball. If moves come later, we'll announce it day by day."
Rosa, who was acquired from Kansas City on May 1, combined to go 2-1 with a 2.76 ERA with 14 strikeouts in 16 1/3 innings in nine games for Reno and Triple-A Omaha. At Reno, Rosa has allowed four hits while walking two and striking out four in four innings in three games.
He has not pitched in back-to-back games this season.
"For me, it's a new opportunity, like I'm getting called up for the first time," Rosa, 25, said. "They told me they were happy to have me here, but I think I'm happier to be here. I'm a little nervous being with a new team and in the big leagues so fast, but I will get over it. I'm really excited to be here."
For his career, Rosa is 0-0 with a 3.21 ERA in nine games out of the bullpen for Kansas City in 2008 and 2009. He made his big league debut June 14, 2008, for the Royals against the D-backs at Chase Field.
"[Rosa's] had a little success up here in his brief time with the Royals," Hinch said. "He has pretty good fastball and a pretty good slider. He's been a little spotty with his control, but he's been pretty tough on right-handed hitters. We'll give him an opportunity and see what he looks like."
Rosa's role in the bullpen is to be determined. Moreover, Hinch did not want to elaborate on possible role changes in the bullpen but did say Chad Qualls will close -- for now.
"It doesn't really matter what I say at this point," Hinch said. "Would I expect Qualls to close? I would. He's available and he hasn't pitched for a couple of days. Defining roles doesn't get us any closer to a win. We'll play the game."
As for Stange, 24, he posted a 13.50 ERA and a .250 opponents' average with six walks and two strikeouts in four games for the D-backs after being recalled on April 28.