Dixon, 27, relayed news of the injury on Tuesday night, when he tweeted a photo of himself in a hospital bed. It was unclear if the photo was taken before or after surgery.
In an ensuing tweet, Dixon wrote, "I'll be back stronger." Wednesday's tweets indicated he is in Pensacola, Florida, and has already started his rehabilitation.
Dixon spent his first four NFL seasons with the San Francisco 49ers before joining the Bills. He tweeted "I love it" when the Bills hired former 49ers offensive coordinator Greg Roman earlier this month.