Headley was injured Sunday while sliding into second base trying to break up a double play.
The injury is not likely to require surgery and will need about a month to heal.
“Injuries occur. You hate to see it happen, but it’s the nature of a physical sport like baseball,” Padres manager Bud Black said. “It’s unfortunate for Chase and the entire Padres organization.”
Headley hit .286 with 31 homers and 115 RBI last year, when he won a Gold Glove and finished fifth in NL MVP voting.
RED SOX: David Ortiz canceled a batting practice session because heel pain that has sidelined the designated hitter for nine days is still too great for him to play.
MRIs last week revealed inflammation in both heels. Ortiz is making his way back from a strained right Achilles tendon.
CARDINALS: Chris Carpenter realizes his baseball career might be over.
The 37-year-old right-hander said he’s still dealing with numbing and tingling sensations in his pitching hand, arm and shoulder.
Asked if he wanted to continue pitching, the former Cy Young Award winner said, “I do. I just don’t think I can.”
DODGERS: Zack Greinke’s first regular-season start will be pushed back by at least a few days.
The Dodgers said the former Cy Young Award winner felt strong Monday, a day after his first bullpen session since receiving an injection in his pitching elbow.
INDIANS: Daisuke Matsuzaka will not make Cleveland’s Opening Day roster.
Trying to make a comeback following elbow reconstruction surgery, Matsuzaka might accept an offer to stay in the club’s minor league camp.
RANGERS: Yu Darvish was scratched from his scheduled start Monday night because of stiffness in his neck.
Darvish said the move is “just precautionary” and that he would have made the start in the regular season.