Britton, 25, is 2-3 with a 5.45 ERA (36.1IP, 22ER) in seven starts for the Orioles so far this season.
In 19 starts for the Norfolk Tides, Britton was 6-5 with a 4.27 ERA, giving up 49 earned runs over 103.1 innings pitched.
Belfiore, 24, went 2-1 with a 3.18 ERA, giving up 27 earned runs over 76.1 innings pitched in 37 games for the Tides.
He has had two prior stints with the Orioles this season but did not appear in a game.
He is looking to make his major league debut.