Los Angeles was leading by three when Kuroda was hit in the head by a line drive in the sixth inning, and the stunned Dodgers watched the Arizona Diamondbacks rally for a 4-3 victory in 10 innings on Gerardo Parra's bases-loaded single.
Tests revealed Kuroda suffered a concussion but no fractures or internal bleeding. He remained in St. Joseph's Hospital overnight for observation.
"It was just shocking," Dodgers manager Joe Torre said. "It certainly caught everybody off guard."
The Dodgers have lost six of eight and their NL West lead has dwindled to 4 1/2 games over Colorado -- their smallest edge since they led by four games on May 13. Los Angeles streaked to a 46-24 start but is 23-24 since June 23.
The Dodgers built a 3-0 lead as Kuroda cruised through five innings, allowing only two hits. But pinch-hitter Rusty Ryal lined a 2-2 delivery off the right side of Kuroda's head leading off the sixth.
The 34-year-old Kuroda crumpled to the mound, clutching his head, as the ball deflected into the seats behind first base, then back onto the field. Ryal was awarded a ground-rule double when play resumed.
"It was scary," Dodgers second baseman Orlando Hudson said. "You always think the worst when you see something like that."
Ryal stopped at first base, then returned to the Arizona dugout while Kuroda was being treated on the mound.
"You get that sick feeling in your stomach," said Ryal, playing in his fifth major league game. "I was just scared. I'm sure everyone else in the stadium, probably even his teammates, have got to be feeling pretty gut-wrenching about it."
Ryal said he sent a message to the Dodgers' clubhouse wishing Kuroda a speedy recovery.
"My thoughts and prayers go out to him and his family, and I hope he's back on the mound soon," Ryal said.
All eight Dodgers fielders stood on the mound as trainers tended to Kuroda, who was placed on a stretcher and loaded onto a cart.
"One of the first things he asked out there was if anybody caught the ball out there, if it was an out," trainer Stan Conte said.
Kuroda raised both of his arms as the cart rolled off the field.
"Amazingly, things look really pretty good," Conte said. "The fact that he didn't lose consciousness is a very good sign."
Conte said the club decided to keep Kuroda at the hospital as a precaution.
"We worry about, even though there's no bleeding now, that there could be in the next 12, 14 hours," Conte said. "That's why we want to keep him at the hospital. The first 12-to-24 hours is important. The doctors feel very, very good."
The Diamondbacks tied it in the ninth against Dodgers closer Jonathan Broxton. Mark Reynolds hit a 431-foot shot off the center-field batter's eye, his 37th, with one out. Three pitches later, Miguel Montero homered into the pool area in right-center field, handing Broxton his fifth blown save in 30 chances.
Augie Ojeda led off the 10th with a single off Ramon Troncoso (4-2) and moved up on a sacrifice by pinch-hitter Dan Haren, who pitched Friday night. Troncoso walked Drew intentionally and Oeltjen unintentionally to load the bases for Parra, who lined the first pitch to the warning track in center field.
"That was a lot of fun," manager A.J. Hinch said. "It was a test of resiliency in playing 27 outs. I think our guys stuck to it to the end."
Chad Qualls (2-1) pitched the 10th for Arizona, which has won consecutive home series for the first time this season.
The Dodgers plan to give RHP Charlie Haeger his second major league start on Monday, in the opener of a seven-game homestand. RHP Chad Billingsley, who missed his last start with a hamstring injury, is scheduled to pitch Tuesday. ... Arizona OF Eric Byrnes, out since June 26 with a fractured left hand, will open a rehab stint at Triple-A Reno on Sunday.