Simmons hurt his finger on a headfirst slide in Sunday’s game at Philadelphia.
The Braves on Monday said Simmons’ hand will be in a cast for four weeks. His status will be updated after the cast is removed.
The injury was confirmed when Simmons was examined by team physician Gary Lourie. Simmons was placed on the 15-day disabled list.
Simmons, 22, began the year in the minor leagues. Another rookie, Tyler Pastornicky, opened the season as the starting shortstop and might be recalled to replace Simmons.
General manager Frank Wren said he spoke with manager Fredi Gonzalez on Monday about the team’s options at shortstop. He said the team likely will make a roster move Thursday.
“Fredi and I spoke this afternoon and we’ve started the process by talking with our scouts and will continue discussions with our minor league staff over the next few days to determine their thoughts on who would be the best fit for our club,” Wren told The Associated Press.
The Braves return from the All-Star break to open a home series against the Mets on Friday night. Atlanta is four games behind first-place Washington in the NL East.
Simmons was called up June 1 and is hitting .294 with three homers and 15 RBIs in 33 games. He was named the NL rookie of the month for June.
Pastornicky, 22, hit .248 with one homer and 12 RBI in 45 games with the Braves. His seven errors helped convince the team to make the change to Simmons on June 1.
Since his demotion to Triple-A Gwinnett, Pastornicky has five errors in 36 games. He is hitting .264 with one homer and 20 RBI.
Pastornicky was regarded as the more polished hitter but Simmons was seen as the superior fielder when the two competed for the starting job in spring training. The Braves want Pastornicky to work at second base and in the outfield in the minors to expand his potential to earn a roster spot as a utility player. That plan might be put on hold if he is recalled to take over at shortstop.
The Braves also have veteran shortstop Jack Wilson.