Schoop sustained the injury while tripping over first base after an at-bat in the fifth inning of Friday's 3–2 loss to the Boston Red Sox. No timetable was given for his return.
"I was tripping over first base," Schoop said of sustaining the injury in his fifth-inning at-bat in Friday's 3-2 loss to the Red Sox. "On the last play [of the game], I felt like my leg was burning. And then walking, I felt like I couldn't move my leg. I woke up stiff [Saturday] morning."
Orioles manager Buck Showalter expressed optimism that the ACL was "in good shape." Schoop will rehab at the Orioles' facility in Sarasota, Fla.
Infielder Jimmy Paredes took Schoop's place on the Orioles' roster and started at designated hitter for Saturday's game against the Red Sox.
Schoop, 23 and in his second season in the majors, said the injury had nothing to do with the hard slide Red Sox third baseman Pablo Sandoval made into second base earlier in the game. Orioles starter Ubaldo Jimenz was later ejected after hitting Sandoval in the shoulder with a pitch.
Over his first nine games this season, Schoop has hit .259 (7-for 27) with a .940 OPS, three home runs and seven RBI.
The Orioles (5–5) are also without shortstop J.J. Hardy, who began the season on the disabled list with a left shoulder sprain.
- Mike Fiammetta