Headley fractured the tip of his left thumb while sliding into second base during a spring training game, jamming it into the bag while trying to break up a double play.
Headley led the National League in RBI last season with 115. The Gold Glove third baseman hit .286 with a career-best 31 homers over 161 games for the Padres in 2012.
San Diego also placed infielders James Darnell and Logan Forsythe on the 15-day disabled list while promoting 12-year MLB veteran utility infielder Cody Ransom and infielder Jedd Gyorko, drafted by the Padres in the second round of the 2010 MLB June Amateur Draft out of West Virginia.
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