The Phillies protected four prospects from possible selection in next month's Rule 5 draft by adding them to the 40-man roster Wednesday. Outfielders Aaron Altherr and Kelly Dugan, catcher Tommy Joseph and lefthander Rob Rasmussen made the cut.

Altherr, 22, and Dugan are both high-ceiling outfielders who started 2013 at single-A Clearwater. Dugan, 23, finished at double-A Reading. Both showed an improved power stroke, although each player still has a long path to the majors. Altherr was recently ranked as the organization's No. 9 prospect by Baseball America.

Joseph's future at catcher is murky because of concussion problems. The 22-year-old was limited to 36 games last season. He was cleared for winter ball action and is currently playing in the Dominican Republic.

Rasmussen, 24, has yet to pitch in the Phillies organization. He was acquired in August from Los Angeles for Michael Young. He projects as a lefthanded reliever and struggled when promoted to triple-A by the Dodgers. He was a second-round pick by Miami in 2010.