The ornamental design for a catcher's mitt, as shown and described.
FIG. 1 is a perspective view of a catcher's mitt according to the present invention;
FIG. 2 is a top plan view thereof;
FIG. 3 is a bottom plan view thereof;
FIG. 4 is a right side elevation view thereof;
FIG. 5 is a left side elevation view thereof;
FIG. 6 is a front elevation view thereof;
FIG. 7 is a rear elevation view thereof; and,
FIG. 8 is an enlarged detail view taken along lines 8-8 of FIG. 2.
It is further noted that the uniform, short-dash broken lines shown in the drawings represent stitching and form a part of the claimed design. The dash-dot-dash broken lines illustrate the bounds of the design and form no part of the claim.