LOS ANGELES -- The Dodgers activated newly acquired reliever Adam Kolarek on Thursday and made room on the 25-man roster by optioning left-handed reliever Caleb Ferguson to Triple-A Oklahoma City.

The 30-year-old Kolarek, a left-handed sidearmer, was acquired on Wednesday from Tampa Bay for Minor League outfielder Niko Hulsizer.

Kolarek, 4-3 with a 3.95 ERA in 54 games, was acquired because the club needed a reliever who can neutralize tough left-handed hitters, president of baseball operations Andrew Friedman said on Wednesday. Lefties are batting .187 with a .238 on-base percentage and .293 slugging percentage against Kolarek.

The Dodgers are thin in left-handed relievers because of injuries to Tony Cingrani, who was traded on Wednesday to the Cardinals despite having had season-ending left shoulder surgery, and Scott Alexander, who is out indefinitely with nerve damage in his left thumb.

Ferguson, 23, has appeared in 27 games for the Dodgers, going 0-1 with a 5.88 ERA.