LOS ANGELES — The Orioles placed Ryan Mountcastle on the 10-day injured list on Monday after he sprained his left wrist and the injury forced him out of the lineup for the past three games. The decision is retroactive to Aug. 23, meaning Mountcastle cannot return until Sept. 2 at the earliest.

To replace Mountcastle on the roster, Baltimore brought back infielder Liván Soto, who has experienced several ups and downs since returning to the organization at the trade deadline this month.

Mountcastle is a key player in Baltimore’s lineup. The first baseman has a .265 batting average and a .730 on-base-plus-slugging percentage. Without him, the Orioles will rely on Ryan O’Hearn and Emmanuel Rivera as their first baseman for the foreseeable future, with O’Hearn likely getting the bulk of the work against right-handed pitchers while Rivera will have to face left-handed pitchers.

The injury, which Mountcastle sustained on August 22 after sliding headfirst into second base on a double in the second inning against the Houston Astros, was initially considered day-to-day. He remained in the game until he was replaced in the ninth inning. However, with no signs of improvement, the Orioles decided to bench Mountcastle for the time being.

O’Hearn, Rivera and Eloy Jiménez should all see more action, with Jiménez coming in as a designated hitter. O’Hearn has often been in a platoon role at first base and as a DH with Mountcastle. He has a .269 batting average this season. Rivera was recently claimed off waivers by the Miami Marlins and is more of a glove-first option with a .213 batting average. And Jiménez, who was traded before the deadline, has turned around a poor season with the Chicago White Sox by posting a .304 batting average since arriving in Baltimore.

Mountcastle’s injury is the latest on a team that has been plagued by setbacks all season. In the infield, Jorge Mateo and Jordan Westburg may not return this season. Mateo dislocated his elbow and has not yet begun baseball activities, nor is he ruling out surgery. Westburg, who broke his thumb when he was hit by a pitch, could be a candidate for a September return.

And pitchers are dealing with even more ailments, including season-ending surgeries for right-handers Kyle Bradish and Tyler Wells and left-hander John Means. Right-handers Grayson Rodriguez and Zach Eflin are both on the injured list, although their respective back and shoulder strains are considered less serious.