Padres' Headley out about a month with thumb injury

San Diego Padres All-Star third baseman Chase Headley was diagnosed with a small fracture in his left thumb and could be out of action for about a month, MLB.com reported Monday.

Headley, 28, jammed his thumb Sunday while trying to break up a double play at second base. He was sent back to San Diego Monday morning to see a hand specialist.

Headley will miss Opening Day, and figures to return in late April.

Headley is coming off a big 2012 season in which he hit .286 with 31 home runs and 115 RBIs. He finished fifth in the National League MVP voting and won his first Gold Glove Award.

He was batting .448 this spring.