Sprained ankle - 13 year old daughter

My daughter sprained her ankle last night while playing tag in the yard with her friends.  Her foot got caught in a tree vine and down she went.  Her ankle immediately swelled up, so I took her to the E.R. for an x-ray.  We were told there were no fractures, and that the ankle was sprained.  My daughter's ankle was splinted and wrapped in a bandage.  The E.R. doctor told me to have her ice it, elevate it and she was given crutches.  We were told to bring her to an ortho. if her pain didn't improve in a few days.  My question is this.  My daughter plays competitive softball.  At what point is it okay for her to begin exercising on the foot?  Also, would bringing her in for physical therapy right away promote healing and help speed up the time she gets back on the field, or is it just a wait and see issue?