How much do you work out off the court?
If you're not, you probably have overworked abdominal muscles that are not used to the movement inherent with greater hip action.
You may have to give the area some time to improve without playing.
Then before you come back work on your crunches, rotating sit ups on a slant board, and maybe some work with a medicine ball.
XL athlete has plenty of core exercises with equipment and http://www.xlathlete.com/browse_admi...38&group_id=15
and without equipment http://www.xlathlete.com/browse_admi...38&group_id=13
[And if you are not getting better quickly, go get checked out medically.]