The ornamental design for a sports stick, as shown and described.
FIG. 1 is a rear perspective view of a sports stick showing my new design;
FIG. 2 is a rear view thereof;
FIG. 3 is a bottom view thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof; and,
FIG. 7 is a top view thereof.
The structural elements depicted by broken lines have been shown for the purposes of illustrating portions of the sports stick that form no part of the claimed design.