Preheat oven to 450˚F (230˚C). Roll dough on lightly floured surface into 15-in. (38-cm) diameter round, about 1/4-in. (5-mm) thick. Transfer to lightly floured pizza pan or baking sheet.
Spread pizza sauce on dough, leaving 1-in. (2.5-cm) border. Scatter mushrooms and green pepper overtop and sprinkle on cheese.
Using pepper strips, make two curving rows of "stitches" to resemble the pattern on a baseball. (Use 12 red pepper strips per row, making "X"s as the stitches.)
Bake pizza on middle rack of oven 18 to 20 min., until crust is golden brown. Let stand 2 min. before slicing and serving.