Jerome Williams is on the disabled list, Dan Haren is set to have his back evaluated Thursday and Ervin Santana is struggling, making now the perfect time for Richards to step up.
"We're thin," Angels manager Mike Scioscia said of the organization's pitching. "Right now we're fortunate that we had some guys like Garrett Richards, who's ready."
After pitching well through his first four starts of the season, Richards looked anything but ready on Saturday in Toronto.
The right-hander allowed 10 runs (five earned) on nine hits in just 4 1/3 innings, including a seven-run second.
"It was just one of those days," Richards said. "I was throwing some good sliders, but I just wasn't getting the swings and misses that I usually do. Four-seam was good, two-seam I thought I had decent control over, but nothing more I can say. Just one of those days. Everybody was off."
The Angels are in desperate need of a long start after their bullpen threw 10 1/3 innings in the past two games.
Five different relievers saw action, with Hisanori Takahashi and LaTroy Hawkins appearing in both games.
The Orioles, on the other hand, will have a fresh 'pen after Chris Tillman took a shutout into the ninth on Wednesday.
The bullpen could become a factor in support of starter Jake Arrieta, who has failed to complete five innings in six of his 17 starts this season, including three of his last six.
Arrieta tied his shortest outing of the year on Friday, lasting just 3 2/3 innings while allowing five runs on eight hits against the Indians.
"They hit some good pitches, some calls didn't go our way, some things happened in the field that ended my night early and caused my pitch count to go up," said Arrieta, who labored through 100-degree heat. "Tonight I really wasn't able to keep my hands dry."
Orioles: Jones reaches 20 homers
Adam Jones notched his team-leading 20th home run of the year on Wednesday, continuing a strong season for the 26-year-old center fielder. Twelve of his 20 home runs have either tied games or given the Orioles a lead, while the team is 16-3 when he homers. Jones has hit 20 home runs in consecutive seasons, although he needed until Aug. 20 to reach the milestone in 2011. Jones also leads the O's in hits (96), RBIs (44) and steals (11).
Mark Reynolds snapped an 0-for-20 skid on Wednesday, when he led off the third inning with a single.
Angels: Morales' bat hot
In his last 10 games, designated hitter Kendrys Morales is 15-for-38. Morales was just 2-for-23 before beginning the current stretch.
Catcher Chris Iannetta (right wrist) is progressing through his throwing program and expects to start a rehab assignment soon.
Vernon Wells (right thumb surgery) is expected to start swinging a bat next week.
The Orioles are 339-285 all-time against the Angels, including 157-157 on the road. The Angels won two of three at home against the O's on May 20-22 before sweeping a pair in Baltimore on June 26-27.
The O's are 6-9 against the American League West.
After opening the season 15-6 away from Camden Yards, the Orioles are 7-11 on the road in their last 18 games.