Coffey was placed on the disabled list Tuesday and replaced on the roster by reliever Shawn Tolleson, who was recalled from Triple-A Albuquerque.
Dr. Neal ElAttrache said Coffey will have a "revision Tommy John," having had an earlier operation to reconstruct his elbow in 1999 while a Minor Leaguer with the Reds.
Coffey blew out the elbow while pitching in the eighth inning Monday night while allowing a triple to the Reds' Todd Frazier. Dodgers manager Don Mattingly and trainer Sue Falsone came out to the mound to determine his health, and Coffey took four warm-up pitches, remaining in the game to finish the inning, even striking out two.
Why did Coffey stay in the game if he had a significant injury?
"That's a question we always ask," Mattingly said. "He said he was fine. He punches out two guys and you sit there not feeling like he's fine, but with the strikeouts you halfway believe him."
This is the second injury of the year for Coffey, who missed 13 games in April with right knee inflammation.
Coffey, whose weight has been listed at anywhere from 240 pounds to 280, has been known for his durability and sprint-in from the bullpen. He was signed as a free agent to a $1 million salary (with a 2013 option for $2.5 million or a $300,000 buyout) shortly before Spring Training started after the Dodgers realized that Blake Hawksworth needed elbow surgery.
The Dodgers now have four relievers on the disabled list that were expected to be in the Major League bullpen: Coffey, Hawksworth, Javy Guerra (expected back this week) and Matt Guerrier.
The 31-year-old Coffey was 1-0 with a 4.66 ERA in 23 relief appearances this season but had allowed just two runs over his last 11 games.
Technically, Tolleson was optioned to Albuquerque on Monday when Luis Cruz was promoted, but Tolleson never left Los Angeles. The club's 2011 Minor League Pitcher of the Year has a 7.71 ERA in six relief appearances with Los Angeles this season.