300mm F/4 versus the 70-300 vr zoom

So after a 2 year hiatus, my daughter has been "recruited" to return to playing soccer for the summer season with the idea that she may be the starting goalie for her high school varsity team in the fall. And here I thought my lens issues were resolved....

I have the 70-300vr zoom but have added a couple nice primes (50mm f/1.8 afs and 85mm f/1.8) to the mix and have really enjoyed using them. I'm now thinking maybe a nice 300mm f/4 lens would be a nice lens for soccer season.

My question is, is the 300mm f/4 prime justifiably better than my 70-300vr zoom for outdoor soccer? Any other (affordable) options I'm missing?

Thank you,

Reid