LAKE BUENA VISTA, Fla. -- The Phillies used 21 relief pitchers last season, so depth can be a serious issue.

The Phils added another arm to their Spring Training bullpen competition Thursday, when they selected right-hander Kevin Munson from the D-backs in the Rule 5 Draft. He went 2-4 with a 4.12 ERA in 53 appearances last season with Double-A Mobile and Triple-A Reno, but has averaged 11.2 strikeouts per nine innings in his Minor League career.

"He's a power reliever, a two-pitch power guy," Phillies scouting director Mike Ondo said. "A big fastball with a hard slider. He's a guy that can create some depth in our bullpen. Get him in the mix. In the past, he's been capable of giving you a two-inning outing. He's also a guy that can come in with that stuff and get a strikeout."

The Phils lost right-hander Seth Rosin to the Mets, who then traded him to the Dodgers. Philadelphia acquired Rosin in July 2012 in the Hunter Pence trade. The Phillies also lost shortstop Jonathan Roof to the Red Sox in the Minor League phase.

"He was a guy we thought we had a chance to lose," Ondo said about Rosin.

But Munson at the very least creates a little more competition for a group that includes Justin De Fratus, Jake Diekman, B.J. Rosenberg, Michael Stutes, Phillippe Aumont, Jeremy Horst and others. Munson's fastball is in the 92-95-mph range, but consistently sits at 93-94 mph.

"I know the ERA was high, but the walks were down in Triple-A," Ondo said. "And his strikeouts were still there. He started getting more ground balls in Triple-A. We saw him both places this year, and we've seen him in the past. We've liked the arm in the past. The way he's progressed, we figured we take a chance on that stuff."

Munson must remain on the 25-man roster the entire season to remain with the organization. If not, another team can claim him or he must be returned to the D-backs.