The ornamental design for a putterhead, as shown and described.
FIG. 1 is a perspective view of a putter head according to my new design;
FIG. 2 is a perspective view of a putter head according to my new design;
FIG. 3 is a front elevation view of the putter head shown in FIGS. 1 and 2;
FIG. 4 is a rear elevation view of the putter head shown in FIG. 3;
FIG. 5 is a top plan view of the putter head shown in FIG. 3;
FIG. 6 is a bottom plan view of the putter head shown in FIG. 5;
FIG. 7 is a side elevation view of the putter head shown in FIG. 2; and,
FIG. 8 is a side elevation view of the putter head shown in FIG. 1.
The broken lines showing the shaft in FIGS. 1-4 and FIGS. 7-8 and the shaft opening in FIG. 5 are shown for illustrative purposes and form no part of the claimed design.