Japanese star Shohei Ohtani suffered a partial shoulder dislocation during the Los Angeles Dodgers' World Series win over the New York Yankees on Saturday, the team confirmed.

Dodgers manager Dave Roberts said Ohtani had been diagnosed with a "little left shoulder subluxation," defined by the US National Institutes of Health as a partial or incomplete dislocation, after he attempted to steal second base in the seventh inning.

Ohtani will undergo MRI scans to determine the severity of the injury, but Roberts said he was "encouraged" after an initial examination of the superstar leadoff man, adding that he expects Ohtani to feature in the rest of the series.

"He had a little left shoulder subluxation, so we're going to get some tests at some point tonight, tomorrow, and then we'll know more in the next couple days," Roberts said.

"But the strength was great. The range of motion good. So we're encouraged. But obviously I can't speculate because we don't get the scans yet. Once we get the scans, we'll know more. 

"Again, with the strength, the range of motion good, that's certainly a positive."

Ohtani was thrown out attempting to steal second base to end the bottom of the seventh.

He appeared to jar his left shoulder as he stretched to slide and stayed on the ground in pain, signalling for help from the team.

He walked off the field holding his left arm, elbow bent, near his body with a trainer in attendance.

While the Dodgers took a commanding 2-0 lead in Major League Baseball's best-of-seven championship series, the injury to Ohtani shocked the crowd at Dodger Stadium.

"You know how big Shohei is for this team," Ohtani's team-mate Teoscar Hernandez said of the injury. "Hopefully he's okay, and the day off tomorrow will help him get back on the field Monday.

"A lot of things go through your head, but you just have to stay positive and think like maybe he jammed his hand and he'll be back on Monday when we start the game in New York."

A two-time American League Most Valuable Player with the Los Angeles Angels before joining the Dodgers this season, Ohtani is expected to claim the National League MVP award this year after becoming the first player to hit 50 home runs and steal 50 bases in a season.

Asked if the Dodgers would be able to cope if Ohtani was ruled out of the rest of the series, Roberts said he wasn't ready to contemplate that scenario.

"I'm not there...I'm expecting him to be there. I'm expecting him to be in the lineup," Roberts said.