Loman, 27, was batting .223/.390/.471 with six doubles, eight homers and 19 RBIs in 39 games at Triple-A Charlotte. He's a career .282/.382/.509 hitter with 123 homers and 424 RBIs in 668 minor league games over eight seasons.
Loman has played 319 games at first base. He also can play the outfield.
MLB.com first reported the trade.
Manager Buck Showalter praised both starting pitchers tonight following the Orioles' 2-1 loss to the Rays at Tropicana Field.
Jason Hammel took the loss after allowing a two-run homer to Desmond Jennings in the seventh inning. Rays starter Chris Archer held the Orioles to one run and two hits over seven innings.
"He was throwing strikes," Showalter said of Archer. "He's got a good arm. He's got some late life on his fastball and (Jose) Molina does a good job with young pitchers and made him slow down just enough. He's got a good slider. He didn't throw that many changeups, but he didn't really need to. We didn't mount much against him. Manny (Machado) took advantage of the one we had and there wasn't a whole lot there.
"Ham matched him. Ham was pitching as well, if not better, up until... There's a fine line there in a game like that and mistakes get magnified. Ham deserved a lot better fate. It was really good to see him pitch as well as he did.
"Ham's pitched some really good games for us since he's been here and will again. He had an extra days' rest with the unfortunate incident last time out that was, we won't debate how that all happened, but he's had some good outings. This was one of them."
The "incident," of course, was Hammel's ejection in the fourth inning of Saturday's start against the Tigers.
The Orioles scored only once in the third inning despite two walks, a single and a wild pitch.
"You let a young guy get his feet on the ground and get his confidence going," Showalter said. "He knows if they can get to a certain inning with their bullpen... Some people say the same thing about us. You had two good teams that played a close game and pitched well on both sides and there was a fine margin for error. Not a whole lot there to critique where I'm concerned. They pitched just a tad better and made one or two less mistakes, but Ham was great."
Machado accounted for the only Orioles run with an RBI single in the third.
"He had all his pitches working for him," Machado said. "He pitched well. He got ahead in the counts. Got the outs when he needed them. Pitched a good game.
"Obviously, we don't have much experience against him, just scouting reports and video. Definitely does make it a little difficult, going into the game not knowing the guy you're going to face so much. You've got to tip your hats. He pitched a great game. Got one run and two hits. Just tip our hats.
"He had all his pitches working for him. He throws 97. He had his off-speed working, threw his slider, changeup for strikes, kept us off balance."