He suffered the injury on Wednesday when Matt Strahm of the Padres hit him with a pitch. Muncy was removed from the game shortly thereafter, and as Bill Plunkett tweets above a Thursday MRI revealed the break. 
This season, the 28-year-old Muncy has batted .253/.375/.525 (135 OPS+) with 33 home runs and 82 walks in 129 games. Along the way, he’s spent time at first, second, and third.  The Dodgers have placed infielder Max Muncy on the 10-day IL with a right wrist fracture. The move is retroactive to Thursday. 
Muncy is optimistic he’ll need to miss just two weeks:  The Dodgers have a safe lead in the NL West and hold a comfortable advantage over the Braves in the race for the best record in the NL, but they’re in a tight struggle with the Astros and Yankees for best overall record in MLB and by extension home-field advantage in a potential World Series matchup with either of the two AL powerhouses.