Los Angeles Dodgers shut down Clayton Kershaw because of back pain

Los Angeles Dodgers' ace Clayton Kershaw has been shut down after he experienced a recurrence of soreness in his back over the weekend.

Kershaw has not pitched since June 26 because of a herniated disk. Manager Dave Roberts told the Los Angeles Times that a date for Kershaw's return to the Dodgers is "uncertain."

The 28-year-old left-hander threw a four-inning simulated game on Saturday and felt discomfort on Sunday. Kershaw has an 11-2 record with a National League-leading 1.79 ERA. His 121 innings pitched, 145 strikeouts, 0.727 WHIP and 0.7 walks per nine innings also lead the league.

"I don't know if it's a step back," Roberts said before Tuesday's game against Washington. "We're going to let the back pain subside and see where we go."

The Dodgers were planning to activate Kershaw in time to start Thursday against the Nationals or on Friday against the St. Louis Cardinals.

Kershaw has not thrown since Saturday and Roberts had no timeline when his ace would pick up a baseball again.

"Obviously, when you're dealing with the back, there's always some concern, certainly," Roberts said. "But you're just hoping in the coming days there is some improvement."

Earlier in the day, the Dodgers placed Hyun-Jin Ryu on the 15-day disabled list and activated outfielder Joc Pederson, who missed 15 games with a slight right shoulder separation.

Ryu had complained of elbow irritation and initially was scratched from his Wednesday start.

Ryu, who missed all of 2015 with a torn labrum, made his first start in 640 days when he faced San Diego on July 7.

He struggled with his velocity and got hit hard giving up six runs in 4 2/3 innings against San Diego.

Los Angeles also recalled lefty reliever Luis Avilan from Triple-A Oklahoma City on Tuesday and placed right-hander Casey Fien on the disabled list with elbow tendinitis.