Richards tweeted a picture of himself on a hospital bed before the surgery, then used social media to announce that the procedure was finished.
''I'm out. Surgery went great! Thank you everyone for your support and positive vibes. I will get through this,'' Richards posted on his Twitter account.
Richards was 13-4 with a 2.61 ERA this year before getting hurt Wednesday while covering first base during the Angels' 8-3 win over the Boston Red Sox. He is on crutches and may rejoin the club next week in Anaheim.
Angels manager Mike Scioscia said that Richards' surgery ''went as expected.'' He added that the timetable for Richards' recovery remains six to nine months.