ATLANTA -- Braves outfielder Jason Heyward had surgery Thursday on his broken right jaw after he was struck by a pitch.
The team has not said how long he will be out, but he could miss the rest of the regular season. Atlanta has a commanding lead in the NL East and hopes Heyward will recover in time for the playoffs.
Dr. Glenn Maron operated in Atlanta, one day after Heyward was injured. He inserted plates in both places where the jaw was fractured.
Before his injury, Heyward had become one of the Braves' hottest hitters. He was batting .253 with 13 homers and 37 RBIs.
The loss of Heyward is the latest in a staggering string of injuries for the Braves this season, even while building a 15-game lead entering Thursday night's game at St. Louis.
Already, the Braves have lost six players to season-ending operations, including starting pitcher Tim Hudson and key relievers Eric O'Flaherty and Jonny Venters.
Heyward got off to a slow start this season, his struggles heightened by an emergency appendectomy in late April. But he sparked the offense after moving to the top of the batting order last month, filling a role that had been a major problem.
The Braves have relied largely on stellar pitching to carry them to the top of the division, ranking second in the league in ERA (3.18) before they faced the Cardinals.
Outfielder B.J. Upton and second baseman Dan Uggla are in the midst of dreadful seasons, both hitting under .200. Uggla is on the disabled list recovering from laser eye surgery. Outfielder Reid Johnson is also on the DL with an Achilles tendon injury and the Braves aren't sure when he'll return.
Barring a trade, the Braves will have to get by with a makeshift lineup. Jordan Schafer seems most likely to take over the leadoff spot and right field. Slugger Evan Gattis is another possibility in left field, which would require Justin Upton to shift to Heyward's spot in right.