Manager Buck Showalter explained to reporters that the club wants Tolleson to get consistent at-bats in the minors.
"He's done a good job for us against left-handed pitching," Showalter said. "If they stay on schedule, that'll be seven to nine straight right-handed pitchers against us. But that's a moving target.
"We obviously had to make room for Lindstrom and we don't want to lose where he is physically. He's ready to go."
Today's transaction leaves the Orioles with a three-man bench and an extra reliever in the bullpen. And Tommy Hunter also is listed among the relievers after throwing two innings last night. He will be available tomorrow night if needed.
"I think with some of the things we're going to have to do in our rotation, we want to make sure we have some length and are covered with our pitching," Showalter said. "We could get back to a position player sometime after the weekend, where we were. We just want to make sure we're covered for the next few days."
Hunter could make the start on Saturday. Eveland also is a possibility, and Norfolk's Miguel Gonzalez would be working on normal rest.
Showalter won't define a role for Lindstrom, who could be used in the sixth or seventh innings, or assist Pedro Strop in a set-up role. Ideally, Showalter would prefer to ease Lindstrom back into the flow, rather than thrust him into a high-pressure, late-inning situation.
"Physically, he's in a good place and we'd like to work him back into it, but we'll see if the game dictates that," Showalter said. "All of a sudden, you play 14 innings here tonight and it's a tie ballgame and he's the guy. But in a perfect world, you'd kind of work his way back into it."
Showalter would like to limit Lindstrom to one-inning appearances for now, but again, he might not have that luxury.
"A lot of that is dictated by your starting pitcher," Showalter said. "I feel comfortable using him a second inning, but I'd like to stay away from it, like a lot of our guys."
Lindstrom was placed on the disabled list May 11 with a slightly torn ligament in his right middle finger.
Jason Hammel will try to become the first Orioles pitcher to not allow an earned run over eight innings or more in three consecutive starts since Jim Palmer in 1978. The franchise record is four straight starts, set by Tom Phoebus May 22-June 6, 1967.
The Orioles are 5-for-52 with runners in scoring position over the last 10 games since going 8-for-17 against the Pirates on June 14. They're hitting .183 in their last 10 games.
The Orioles have scored three runs or fewer in nine of their last 10 games, and their 20 runs scored since June 15 are the fewest in the majors.
The Orioles have drawn 37 walks in their last 13 games, but only four of those runners came around to score.
For the Angels:
Mike Trout CF
Torii Hunter RF
Albert Pujols 1B
Kendrys Morales DH
Mark Trumbo LF
Alberto Callaspo 3B
Howard Kendrick 2B
Erick Aybar SS
Bobby Wilson C
Jered Weaver RHP
NOTE: The Orioles announced that they've agreed to terms with their 29th-round pick, right-hander Jake Pintar. They've agreed to terms with 24 of their 40 selections.