We won't get a better idea of if Calvin Johnson will be able to play against the Giants until later in the week, but Jim Schwartz said today that he is "very concerned" about Megatron's shoulder injury. He also added this:
"We’re doing some tests today," Schwartz said. "He’s no worse than he was yesterday, but it’ll probably be something that will develop through the week. He wasn’t able to finish yesterday; we’ll see if we can get him on the practice field this week."
Had the Lions practiced today, Johnson would not have been able to give it a go. Even so, we won't know more about his injury until Detroit hits the practice field on Wednesday. If he still isn't able to practice, then it may be time to start worrying about him not playing on Sunday. For now, though, I'm just going to wait and see what happens.