"He really seemed to be throwing better tonight," Angels manager Mike Scioscia said. "We liked his stuff and it is something to build off of."
In Santana's five innings of work, he gave up six runs, four of which were earned. With the loss, his record fell to 1-4 with a 7.43 ERA.
"The ball was coming out of my hand really well tonight, I just had a few location mistakes, Santana said.
"My pitches had more life than earlier this year and I really was not scared to throw any of my pitches. I felt good."
Throughout the game, Santana's velocity reached 93 and 94 mph, an encouraging sign for both Santana and Scioscia.
"Before with my injuries I was thinking about the pitches I was throwing, but tonight I was not scared to throw," Santana said. "Before this, I think the injuries were a factor in my velocity."
Even though Santana pitched relatively well Friday, the Angels didn't help him out in the field or at the plate.
In the first inning with a runner on first, Angels shortstop Erick Aybar booted a double play that would have ended the inning. Instead, only three batters after the error, designated hitter Luke Scott hit a two-run double, scoring both runs that would have been outs had the earlier play by Aybar been made. Those two runs eventually made up the difference between the two clubs.
"That one play really set the tone for that entire inning," said Scioscia.
Baltimore's big inning came in the third, as with runners on the corners and no one out, first baseman Aubrey Huff hit a three-run home run just over the wall in right field, making the score, 5-0.
Minus a two-run home run by first baseman Kendry Morales to right field in the bottom of the sixth inning, the Halos weren't able to take advantage of many scoring opportunities.
All of Morales 14 home runs this season for the Angels have been when he bats from the left side.
Second baseman Maicer Izturis singled twice and doubled in a run and Juan Rivera continued swinging a hot bat, hitting a single and a double on his 31st birthday.
However, the Angels' two, three and four hitters were 1-for-11 in the game.
"We missed some opportunities tonight and couldn't do quite enough to get the win," said Scioscia.
The team missed an opportunity to get on the board in the third inning, when with no one out and runners on first and second, the Halos couldn't plate a run home. Aybar grounded into a fielder's choice before Chone Figgins popped up to short and Bobby Abreu grounded out to second.
Both Aybar and Figgins didn't have good averages against Orioles starter David Hernandez going into the game. Aybar didn't have a hit in six at-bats, while Figgins was just 1-for-9.
The Angels made it interesting in the ninth, as Izturis singled to bring the tying run to the plate, however after a Jeff Mathis strikeout, pinch-hitter Mike Napoli hit into a game-ending double play.
After Santana exited the game in the fifth inning, the Angels' relief combination of Kevin Jepsen, Rich Thompson and Matt Palmer gave up no runs in four innings of work.
"We really needed all of them tonight," Scioscia said. "They kept us in the game, we just couldn't get enough runs across."
Quinn Roberts is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.