Josh Towers, whose Friday start was washed out, will start in place of Kuo on Saturday.
Kuo's injury was revealed only moments after Friday's exhibition game was rained out, back-to-back blows to a goodwill series that had started so upbeat.
But Kuo's news, unlike the rainout, could impact the roster and the season, especially with the continued absence of fellow setup man Ronald Belisario, indefinitely stuck in Venezuela with visa problems.
The Dodgers' bullpen, considered last year to be a team strength, is uncertain halfway through Spring Training. Jonathan Broxton is healthy, but George Sherrill has had some nagging injuries. Now Kuo is down.
Only four days earlier, Kuo was unhittable in his exhibition debut against Colorado with a pair of strikeouts in one perfect inning. But he said he felt soreness in that appearance and it bothered him again Friday during a bullpen session at Tienmu Stadium, after which he first reported it to the team trainers.
"I just found out today," said Torre.
Kuo downplayed the severity of his discomfort.
"After the first game, it felt sore. I think it's like normal spring [soreness]," said Kuo. "Yesterday's bullpen, it feels the same. It's getting better. I feel OK to pitch. I [don't] want it to get worse. Shut it down and get ready for the season. I know it's going away in a matter of time. It's not a big deal.
"But it's very sad. I was hoping to pitch for my family. But I've got to take care of myself and get ready for the season."
Nonetheless, when you have a medical history like Kuo's, no elbow injury is minor.
Kuo was signed out of Taiwan for $1.25 million as a teenager, and blew out his elbow in his first professional game after striking out seven of the 10 batters he faced. It's been a wild ride ever since, including the first five years he spent trying to get healthy, when he pitched a total of 42 1/3 innings (averaging less than nine innings a year).
He's nothing if not persistent. He signed in 1999, meaning he's been in the organization longer than any current active Dodger other than Jason Repko, who signed a week earlier. That year, Kevin Malone was general manager, Davey Johnson the field manager and Gary Sheffield and Eric Karros hit 34 homers. Each.
Kuo's journey to the Major Leagues hit one pothole after another. He missed 2003 entirely, was taken off the Major League roster at one point, and could have been selected by any club in the Rule 5 Draft. When his rehab stalled for the umpteenth time, he had to be talked out of quitting the game. He has often credited Darren Dreifort (two Tommy John surgeries) and Eric Gagne (one) for their advice and counsel to keep him going. As recently as 2007, he had rotator cuff problems and elbow surgery and his career was in jeopardy.
But Kuo is nothing if not determined. He showed up for Spring Training in 2008 with a new manager, not really counted on for anything. He caught Torre's eye with two scoreless innings of relief against the Padres during the Dodgers' goodwill series in China and made the club. He went on to win MLB.com's Setup Man of the Year Award, but the workload got to him and he came up sore in September.
Those problems carried over to 2009, when Kuo struggled through Spring Training discomfort. And when the pain went away, so did his control. He missed two months with what amounted to the yips, unable to throw catchable pitches, let alone strikes. But he battled back from that and had a 2.19 ERA after the All-Star break.