Diekman and De Fratus optioned out

Phillies reliever Jake Diekman. (David Maialetti/Staff Photographer)

CLEARWATER, Fla. --The Phillies continued to trim their roster Sunday morning and for the first time two guys who were part of the competition for bullpen spots were among the cuts.

Lefthander Jake Diekman and righthander Justin De Fratus were optioned to the minor-league complex, leaving Raul Valdes, Phillippe Aumont, Jeremy Horst, Michael Stutes and Aaron Cook as the top five candidates to fill out the final three spots in the bullpen.

Diekman and De Fratus both pitched in the big leagues last season and have two of the best arms in the organization, but pitching coach Rich Dubee said they need more work in the minors.

"Diekman has to learn to pitch backwards," Dubee said. "We want him throwing more changeups, using his changeup some to righties. We want him using first-pitch breaking balls and in 1-0 counts to lefthanders so people can't get started and cheat on his fastball. He also needs to command all three."

The 26-year-old lefty posted a 4.50 ERA in eight Grapefruit League appearances, allowing five runs on 12 hits and four walks in 10 innings. His 12 spring strikeouts are a clear indication of his potential. Diekman appeared in 32 games with the Phillies last season and was 1-1 with a 3.95 ERA.

Dubee said De Fratus still needs to build his arm strength.

"His arm is a little bit behind right now," the pitching coach said. "His breaking ball is a little too big. He's aware of that. I think he got started a little bit slower this year for whatever reason, but he'll be back in the picture soon. He's got plenty of stuff. He just has to get more reps and get it going."

De Fratus, 25, admitted Friday that he started a little bit slower with his long-toss throwing program this offseason because he suffered elbow soreness last year when he pushed too hard too soon. His first two outings of the spring were shaky, but he allowed just one run over six innings after that. Overall, he had a 6.00 ERA in seven appearance, allowing six runs on 10 hits and four walks in nine innings. He only had two strikeouts this spring.

In the last two seasons at the big-league level, De Fratus is 1-0 with a 3.07 ERA in 18 games.

"They're valuable pieces," Dubee said of Diekman and De Fratus. "Right now, they're not there, but they're in the picture for sure. We expect if we have an issue or something, those guys will be mentioned for sure."

In the meantime, the Phillies must sort through the remaining candidates to open the season in the bullpen.

Jonathan Papelbon, Mike Adams, Chad Durbin and Antonio Bastardo are locks to make the team.

Aumont, Horst, Stutes and Valdes would appear to be the most likely candidates to fill the final three spots in the pen unless the Phillies decide to keep Cook, a veteran big-league starter, as their long man.

Valdes, who had a 2.90 ERA in 27 games last season, has made a strong case to fill the long-reliever role by stringing together six scoreless innings in his last two outings.

Horst is coming off an outstanding 2012 season in which he went 2-0 with a 1.15 ERA in 32 games. Stutes had a strong 2011 season, but missed most of last season with a shoulder injury. Aumont has the most overpowering arm among the bullpen candidates.

In addition to optioning Diekman and De Fratus, the Phillies also reassigned lefty Cesar Jimenez and infielder Josh Fields to the minor-league complex.

Happy St. Patty's Day

Roy Halladay will make his first start since his turbulent 2 2/3 innings Tuesday against Detroit by pitching against the Baltimore Orioles Sunday. He will also hit for the first time this spring.

The Phillies' hitters will face righthander Jason Hammel.

The lineup: Ben Revere, CF, Freddy Galvis, SS, Chase Utley, 2B, Ryan Howard, 1B, Michael Young, 3B, Domonic Brown, RF, Darin Ruf, LF, Erik Kratz, C, Roy Halladay, P.