KANSAS CITY, Mo. -- Maybe the Kansas City Royals can get a two-for-one special on Tommy John surgeries from Dr. Lewis Yocum.
Yocum will perform the operations at his office in Los Angeles.
"They did the hard part getting to the big league level before they had these surgeries," Royals manager Ned Yost said, "so we expect these guys to come back every bit as strong, or stronger, than before the injuries occurred."
The Royals already lost closer Joakim Soria to his second Tommy John surgery during spring training, and hotshot prospect John Lamb had the same surgery last year.
Duffy, the team's best starter early this season, suffered a partial tear of the ulnar collateral ligament in 2010. Wood first hurt his elbow during the 2009 season.
"They're all different. Everybody's different," Yost said. "You get to a point where it's a tear that you think you can rehab and continue to pitch with, you shut down and let inflammation come down and heal as much as you can, and you go back to pitching another year or two or three.
"When it gets to the point where it doesn't look like that will happen, where any amount of shutdown won't let them go out, that's when they decide to go in and replace it."
The 23-year-old Duffy opened 2-2 with a 3.90 ERA in six starts, at one point drawing rave reviews from Tigers manager Jim Leyland during a losing effort.
The left-hander missed a start with tightness in his elbow a few weeks ago, but came back to pitch well in a win over the Yankees. He struggled his next time out against Boston, and was pulled from his start last Sunday against the White Sox after just 13 pitches.
Duffy was initially diagnosed with a torn ligament on Monday.
Wood, who went 5-3 with a 3.75 ERA last year, opened the season on the disabled list because of what the team called an ulnar nerve irritation. The right-hander remained at the club's spring training complex in Surprise, Ariz., attempting to rehab without needing surgery.
"The surgeries they keep doing are so efficient, you know, it just depends on the person," Yost said. "Chris Capuano was a kid I had in Milwaukee. He had Tommy John and then had another one, and he's pitching at a very high level in Los Angeles right now."
Royals pitcher Bruce Chen underwent Tommy John surgery in 2007 and missed the next season but was back in the major leagues the following year. Soria had the surgery in 2003 and returned to become an All-Star closer before undergoing the same procedure in April.
Yost said Friday that Soria's rehab is on schedule.
"He's doing great. He hasn't had any setbacks," Yost said. "He's right on progress."