Belfiore made two appearances this spring, giving up one run on five hits with one strikeout in two innings. He spent most of last season in Norfolk, where he compiled a 2-1 record and 3.18 ERA in 76 1/3 innings over 37 appearances.
Alderson gave up five runs on four hits and a walk without recording an out in his second and final Grapefruit League appearance on Monday. Additon also appeared in two Grapefruit League games, allowing two runs on three hits in two innings of work.
The Orioles now have 59 players remaining in Major League camp, including 19 non-roster invitees.
Adam Berry is a reporter for MLB.com. Follow him on Twitter at @adamdberry. This story was not subject to the approval of Major League Baseball or its clubs.