Yes, as people have said it can be done. Find a local tailor near you that has great reviews, etc. The one i went to does wedding dresses and such. I think a big factor is the material also. I had a Pete Rose baseball jersey tailored in almost every aspect and it turned out perfect. It was about 65$ all said and done and that included moving the M & N tags that sit on the bottom of jersey as well. I took in a Barry Sanders football jersey (mesh with other material) and they wouldn't touch it. They said the mesh and altering would basically be difficulty and not turn out right.
If your just shortening the length it should be simple and relatively inexpensive. Good luck