Manager Paul Warne expects the 25-year-old to miss the next six to eight weeks after he left the pitch during the Millers' 3-0 win over AFC Wimbledon last Tuesday.
Jamie Lindsay has missed just two league games for Rotherham United this season and did make the trip to Cheltenham Town on Saturday but was in the stands as his side recorded a 2-0 victory to jump to fourth in the League One table.
"It's a bad result from the scan," said manager Paul Warne.
"He made an innocuous landing and the force through his leg made his hammy tear quite significantly.
"He travelled down this weekend because he didn't want to miss out. He trained on the morning of the game in the pool at the hotel and did gym work. He doesn't want to not be involved."
Paul Warne is confident that the midfielder will be back within six weeks. The upcoming international break means he will miss approximately five games.
"He didn't take it well at first although when I saw him on Friday he seemed a bit better," added Paul Warne.
"Life is too short to be unhappy for too long. He doesn't take injury well and he wants to play every minute. He's a competitor.
"Knowing Jamie and the man he is, if the physio says six to eight weeks it will definitely be six not eight. I look forward to seeing him back."