An MRI on Braves shortstop Andrelton Simmons’ right thumb revealed a bone bruise, the team said Monday.

Braves manager Fredi Gonzalez said Simmons’ injury improved significantly but he was out of the lineup against the Giants at Turner Field on Monday. After X-rays on the thumb were negative, Simmons underwent an MRI exam in Atlanta on Monday.

“I think that the good thing is from yesterday to today was a big improvement,” Gonzalez said. “We’ll see what tomorrow brings us with him and hopefully there’s a lot of improvement there and we can sit on it a little bit.”

Simmons injured the thumb while attempting to make a diving catch in the seventh inning of the Braves’ 12-2 loss to the Phillies on Saturday. The two-time Gold Glove winner is one of the top defenders in baseball at his position.

Rookie Daniel Castro started his second consecutive game in place of Simmons.