BALTIMORE -- It was a costly day for the Orioles pitching staff.

The club placed both Alex Cobb and Nate Karns on the 10-day injured list Tuesday, the right-handers suffering from lumbar strain and right forearm strain, respectively. Right-hander Evan Phillips and left-hander Josh Rogers were recalled from Triple-A Norfolk in their place.

Rogers was scratched from his start at Norfolk to provide depth behind Dan Straily, who will start in place of Cobb on Wednesday. The injuries also mean John Means, who made his first Major League start in Tuesday’s 13-2 loss to the A’s, remains in the rotation for at least another turn.

This marks the second IL stint already this season for Cobb, who began the year inactive due to a right groin strain. It is backdated to April 6. He was not immediately available to discuss the ailment, which had not been disclosed until Tuesday. "He's got some back spasms," Orioles manager Brandon Hyde said of Cobb. "He felt good yesterday. Then today he went out and threw and his back tightened up on him a little bit."

For Karns, evidence of an injury was more plain to see. Karns' velocity diminished significantly during Monday's 12-4 win over the A's, which he finished with a scoreless inning. The radar guns "spooked some guys," said Karns, who characterized the IL stint as precautionary. The righty averaged 88.5 mph Monday with his four-seam fastball, per Statcast, down from 90 mph in his previous appearance, and 90.9 the outing before. All told, Karns' average fastball velocity has decreased steadily since his season debut March 30.

"It's just tightness. There's no pain," Karns said. "Normally, I don't throw 88-89."

Said Orioles manager Brandon Hyde: "We felt like the best thing was to almost hit the reset button."

Karns was the club's lone free agent signing this winter, and his season debut marked his first game action since May 2017, after the righty missed most of the past two seasons with injuries. He underwent surgery for thoracic outlet syndrome in July 2017, then sat out all of 2018 due to elbow discomfort. Karns has also undergone Tommy John surgery. He was shut down briefly this spring after struggling to stretch out, ultimately settling into a bullpen role.

"Last year, I couldn't even pitch in a game," he said. "This is just a minor setback, which is something we feel like if we squash now it will be better off for us in the long run."

The right-hander, 31, is 16-12 with a 4.30 ERA in 67 career appearances, most coming in a starting role before arriving in Baltimore. With the Orioles he's made two, both as an "opener," to go along with two relief appearances, allowing seven hits but just one unearned run over 5 1/3 innings overall.

Hyde had alluded to potential bullpen turnover Monday night, to supplement a unit that's been among the heaviest-worked in baseball thus far. If you include Karns' two two-inning starts in an opener role, Hyde asked his 'pen to cover 54 1/3 innings over the club's first 11 games, largely to cover the hole Cobb's balky groin left in the club's rotation. Even with Cobb back in the fold, the Orioles saw it necessary to add free agent Straily this week, and plug Means into the rotation on Tuesday. Baltimore relievers have posted a 7.87 ERA this season.

Enter Phillips, who was one of the last cuts this spring after a stellar showing in Grapefruit League play. One of the four players acquired for righty Kevin Gausman last July, Phillips went unscored upon across eight appearances this spring. Phillips has a 10.43 ERA in 10 career big league appearances, nine of them coming last year with the Orioles and Braves, plus the three scoreless innings he threw Tuesday, marking his season debut.