Two years ago, Kuo attempted a similar bullpen session and airmailed two pitches onto the field that stopped play. This time he wasn't as wild, but he was wild enough.
Manager Don Mattingly said Kuo had an MRI of his back last weekend in San Diego that showed some sort of change, although that's no surprise for any pitcher with 11 years of professional experience, especially one with Kuo's history of injuries that includes four elbow operations.
"We were trying to figure out why he's up, up, up," Mattingly said of Kuo, who has four walks in 2 2/3 innings after walking only 18 in 60 innings last year. "He's going to rest the next couple of days and have some tests done."
Mattingly was not specific on the tests, but coming back from the yips is test enough. It took Kuo three months of rehab in Arizona in 2009 to get him back to the big leagues and there were plenty of people in the organization who wondered if he'd ever make it. Not only did he return, but he helped in that year's playoff run and followed with his best season in 2010, setting a franchise-record 1.20 ERA.
The 29-year-old Kuo was not at Dodger Stadium on Saturday night, but Thursday night he discounted injury as an explanation for his wildness.
"It's not because of my elbow, my shoulder or my back," Kuo told the Los Angeles Times. "I just have to make a pitch."
In his last outing, Wednesday night in San Francisco, Kuo's fastball was consistently clocked at 93-94 mph.
"The good part is it's not the elbow or shoulder," said Mattingly. "The MRI didn't show major stuff. We feel like it's muscles and hope to get it worked out."
Kuo has been in the organization longer than anyone else on the roster. He's survived five Dodgers managers, five general managers and two owners. Signed out of Taiwan at age 17, he struck out seven of the first 10 batters in his professional debut and also blew out his elbow, leading to the first of two Tommy John operations. After his second operation, he had to be talked out of retirement by teammates Darren Dreifort and Eric Gagne and Acey Kohrogi, executive director of Asian operations.