“Dream Momma, I’ve been reading your blog and decided to write you. The other night I had a dream that my lower leg was injured (I'm not sure how), but it was a bad enough injury that it had to be amputated. I remember my lower leg being gone and not being upset. The next thing I remember is that I was getting a prosthetic leg. I felt very comfortable… never upset or sad. I thought my "new" leg was "cool" and I was proud. I could run, dance, and lead a normal life. In real life I play a lot of sports but I don’t think it was about sports." (sic)

You’re right. It is not about sports. Archetypally the leg can symbolize elevation, speed, erection, energy, and supremacy. We can assume since the leg (or whatever it symbolizes) was seriously injured a prosthetic would be a relief.