Miner operator and M.R.S. operator set up in #2 Block to begin pillaring. The right rib popped and rolled hitting M.R.S. operator on right calf. After checking roof and rib again, they loaded out first lift before end of shift. On way to mantrip, M.R.S. operator said his leg was wet and discovered a tear in his calf. He was transported to hospital for sutures.