"We absolutely expect him back," said Colletti, who added that it should be in the first half of the season. "We'd rather do this now than go all season long with it. This is the best course of action."
Padilla has been working out at Camelback Ranch-Glendale for three weeks, but Colletti said it wasn't until he started to crank up his velocity last week that the discomfort -- which sidelined him for two months last year -- returned.
Dodgers reliever Eric Gagne had ulnar nerve entrapment surgery in June 2005 and missed the rest of the season. However, that was a different nerve, and recovery times vary depending in part on the extent of nerve damage.
Padilla will undergo the surgery at Kerlan-Jobe Clinic by Dr. Neal ElAttrache and return to Arizona Friday. He was examined by ElAttrache on Monday at Camelback Ranch-Glendale and sent to Los Angeles on Tuesday for testing after experiencing pain following a Sunday bullpen session.
The 33-year-old right-hander was signed to an incentive-laden contract (with a $2 million base) after battling through the arm problem and a bulging disk in his neck last year. Colletti said Padilla's health history was taken into account both in the negotiations and the decision to have Padilla be a reliever instead of a starter.
At the time, the club already had a five-man rotation (Clayton Kershaw, Chad Billingsley, Ted Lilly, Hiroki Kuroda and Jon Garland). Management was hoping to use him as a swingman who could pitch multiple innings of relief, start occasionally and provide an alternative if closer Jonathan Broxton struggles.
"When we signed him, we made the decision to start him in the 'pen," said Colletti. "If we had made the decision to have him be a starting pitcher, we'd be looking at a longer rehab.
Padilla went 6-5 with a 4.07 ERA in 2010 and made only 16 starts. He experienced similar discomfort last Spring Training but pitched through it and was the Dodgers' Opening Day starter, allowing the Pirates seven runs in 4 1/3 innings.
After his fourth start April 22 in Cincinnati, Padilla complained of so much arm pain that he couldn't move his arm and was shut down, diagnosed with a bruised radial nerve in the forearm that can refer pain from the shoulder to the fingers. When he was healthiest in midseason last year, Padilla strung together six consecutive quality starts with a 1.30 ERA.
Although agreeing to serve any role he was asked, Padilla came to camp this spring determined to show he could still be a starter. The Dodgers, after Padilla's inability to stay healthy last year (pitching only 95 innings) signed Garland to be the fifth starter and felt Padilla had a better chance of staying healthy by relieving.
Padilla's injury and the continued absence of Ronald Belisario (visa issues) underscore the importance of signing free-agent set-up reliever Matt Guerrier, and improve the chances of Kenley Jansen and Blake Hawksworth to make the Opening Day roster in the bullpen, as well as Jon Link, Carlos Monasterios, Ramon Troncoso and a long list of non-roster pitchers that includes veterans Lance Cormier, Mike MacDougal and Ron Mahay.
"I said if everybody stayed healthy, [Padilla] was probably in the bullpen," said manager Don Mattingly. "Guys fighting for a bullpen spot will continue, and now there's another one -- for how long, we don't know. There's competition for jobs, so we'll see."
An 11-year veteran, Padilla was signed as a free agent during the stretch run of 2009 after being released by the Texas Rangers. He went 4-0 with the Dodgers and stepped up with dominant starts in the playoffs to earn a $5.025 million, one-year contract for 2010.