I'm not a doctor and I didn't stay at a Holiday Inn last night.
But, let's say it's a slight tear. What is the harm in playing him? One of two things is going to happen. It's going to tear the rest of the way...or...he plays through it.
If it tears the rest of the way, he is out for the year and gets surgery now instead of after the season. If it doesn't tear, he would probably have surgery after the season.
Neither case would affect him long term after recovery from surgery.
I'm failing to see the harm in playing him if this is the case.