No problem
As for the Parker situation. With some injuries, there are tried and tested treatments that usually see a player return by an expected date. Inflamed muscles and breaks are far easier to deal with within a known window. Occasionally they can recover more quickly or take a little longer. However, with some injuries the complications are too variable to predict, so no return date can be set until recovery has been assessed. They may also have more than one problem and may need to come through one aspect of the injury before than can solve the other.
Parker's injury requires a slow recovery, building up the strength gradually. If he comes back too soon he risks further damage. I had a heel injury and it has taken me months to recover from, have to treat it with kid gloves now too.