MIAMI -- Patrick Corbin will join the D-backs' starting rotation Monday when he starts against the Marlins in place of Josh Collmenter.

Collmenter, who is 0-2 with a 9.82 ERA in four starts, will head to the bullpen, where he will serve as the team's long man.

The team will make a corresponding roster move when Corbin joins the team, likely on Sunday.

In four starts with Double-A Mobile, Corbin is 2-0 with a 1.67 ERA. That comes on the heels of an outstanding Spring Training in which he almost made the team.

Arizona manager Kirk Gibson was not very revealing when asked about the reasoning in choosing Corbin, but general manager Kevin Towers cited a number of factors.

"It's a tough decision," Towers said. "We've got several guys down there throwing well. He performed very well in Spring Training, he's been in pro ball maybe a little bit longer than some of the others. We've looked at the National League, and most clubs have been struggling against left-handed pitching."

It's likely that fellow Double-A hurlers Tyler Skaggs and Trevor Bauer were considered for the start.

"We just felt like he was the right guy," Towers said. "That's not to say that some of those other guys at some point in time may get an opportunity as well."

No timetable as injured D-backs progress

MIAMI -- While injured D-backs players Chris Young, Stephen Drew and Daniel Hudson continue to make progress in their individual rehabs, there is still no timetables for their respective returns.

Drew (ankle) played three innings of an extended spring game on Friday, Hudson (shoulder) played catch from 60 feet the same day and Young (shoulder) continues to receive treatment.

"I wish I had a crystal ball to know exactly when C.Y. and [Hudson] will be back," D-backs general manager Kevin Towers said. "It would really help us for planning purposes, but until [Hudson] really gets up and starts letting it go, we won't really know."

Drew's 2011 season ended in July, when he suffered a devastating right ankle injury. Towers said he plans on going out to watch Drew when the team returns home next Monday following this 10-game road trip.

"He's feeling better and better, less stiff in between times that he plays," Towers said. "He's getting close. It will be nice to see where he's at when we get back home."

Overall, Towers said he has been happy with the way his 10-10 team has played so far this year.

"They've been a resilient bunch," Towers said. "We've played great defense, which has really been good other than that game we made five errors. We've defended very, very well. For the most part, our bullpen has been good. We haven't blown many games late."