SAN DIEGO -- Padres left-hander Clayton Richard will miss the rest of the season after undergoing arthroscopic shoulder surgery on Friday.
Padres team physicians Dr. Heinz Hoenecke and Dr. Jan Fronek smoothed out the glenoid labrum, biceps tendon and rotator cuff.
Manager Bud Black said the exploratory surgery was to find out why Richard has not responded to treatment since he was placed on the 15-day disabled list on July 5 with a strained left shoulder.
"He wasn't progressing to the point where rehab or a strengthening program was going to help," Black said.
Richard met with renowned orthopedist Dr. Lewis Yocum on Thursday to get a second opinion on his ailing shoulder. Yocum recommended the surgery, which was performed by Dr. Heinz Hoenecke, the team orthopedic surgeon for San Diego.
Richard initially was upset with the team's decision to place him on the DL, insisting he could pitch through the issue. But the shoulder did not respond and the team's medical staff wasn't sure why.
The 6-foot-5 Richard went 5-9 with a 3.88 ERA in 18 starts this season.