Klein 50/50 for tomorrow's game...according to AV. Says Klein was sore after practice. I'd be surprised if he played, being up 3-1.
When you don't work out for a while, you get extra sore after the workout. That doesn't mean you are injured and it will go away, but you feel very uncomfortable. (It's also the reason most people quit after their first good workout: "OMG, I can't move, this is awful, my body is clearly not made for working out.")
If that's the case, he may as well be ready tomorrow. The 36 hours from today in the morning to tomorrow's game is more than enough for him since he's not some noob that never worked out, he just took a break for a few weeks. They could've just given him a day off since there's no point in making him extra-sore right before the game.
I don't know that this is a fact, but people need to stop with their medical diagnoses based on no medical information. He could've reinjured himself or he could be sore or he could've broken his toe nail 5 minutes before the practice, we have no idea. But the fact that he needed a "maintenance day" is not proof that he was re-injured, he legitimately could be sore because he's just getting back into shape.