Los Angeles Dodgers ace Clayton Kershaw leaves start early because of low back pain

SAN FRANCISCO -- Los Angeles Dodgers left-hander Clayton Kershaw left his start Thursday at San Francisco because of low back pain, the team said.

Manager Dave Roberts said after the 4-2 win that Kershaw's back tightened on him after a warm-up pitch before the bottom of the fifth inning. The three-time NL Cy Young Award winner winced and pointed to the dugout, and then he walked off the field gingerly with a trainer.

Roberts said Kershaw will get testing in Los Angeles on Friday.

Kershaw said he didn't feel any back pain until the fifth inning.

"Just felt something kind of lock up there in the fifth and couldn't really throw after that," he said.

The 34-year-old Kershaw made 66 pitches through four innings, allowing one earned run and three hits with four strikeouts. He left with a 4-2 lead.

Kershaw spent time on the injured list earlier this season due to inflammation in a pelvic joint. He was 7-3 with a 2.66 ERA in 14 starts entering Thursday's game.

Right-hander Phil Bickford came on in relief. The NL West-leading Dodgers got their fifth straight win.

The Associated Press contributed to this report.