I know many lawyers, and, from what I have heard, your first year of law school your head will be spinning, you will be doubting yourself, etc etc. You will want to have as much "free" time as possible to spend in the library, studying, etc. Some schools do not allow you to have a part-time job. That should tell you how demanding it is. I definitely would not plan on having a regular scheduled activity (team practice and games) during the first year. However, I think an occasional pick-up game would be good as a stress release, as would jogging, working out, etc.
Second and third year students start getting into the actual practice of law. The law schools have law clinics which are comprised of students who are helping the needy. There is also the law school's law review journal, where students research and write about legal issues. You will want to get into one or the other of these, or some similar program, as, it will look good on your resume! Again, while the focus is school, you will want some sort of physical activity for stress release. It just shouldn't take up too much of your time!
Between 2nd and 3rd year, during the summer, law students normally find jobs working for attorneys, just for the summer.
All of these other activities will need to take priority over organized sports, while you are in law school. Once you graduate, you may have more time for sports. You may not. "Baby" Attorneys tend to work somewhere between 50 and 70 hours a week. It's a lot of work.
There are many alternatives available other than becoming an attorney. One would be to become a paralegal. This is usually a 2 year program, rather than the 7 years it takes to become an attorney. Paralegals do a LOT of the work for the lawyers. This includes research and writing. Each state has different requirements. If you want to go to school to become a paralegal, please choose your school carefully. There are many schools that do not have a good reputation. You will want to look for one that has an ABA (American Bar Assn) approved program.
Good luck to you!