"It got him," D-backs manager Bob Melvin said. "For me, it was worse than any of the other ones he had. He's a pretty tough cat for him to just be automatically out of the game. ... It looked like he had the base stolen, too. Just a step or two before he started to go into his dive, it went on him. It's definitely DL. How long? We're not sure."
Before the double, Byrnes was mired in a 2-for-22 slump since coming off the disabled list. He was moved down to seventh in the lineup on Monday night.
Melvin was asked before the game if he thought Byrnes was at 100 percent health-wise, and he gave a very candid response.
"I think he's healthy, he's just struggling with his performance right now," Melvin said. "He's not getting on base. When he came back, he was really excited about getting back and giving us something, and giving us a little bit of a jump-start. He hasn't been able to do it at this point. I really don't think he's been out there enough, as far as running the bases and trying to steal bases and so forth."
Byrnes was replaced by reserve outfielder Jeff Salazar.
The D-backs also lost Snyder in the fourth inning after Corey Hart fouled off a ball that appeared to hit Synder in the groin. Snyder fell to the ground and winced in pain. His injury was described as a contusion, and he is listed as day-to-day.
"That wasn't good," Melvin said. "The swelling went down a little bit afterwards."
Snyder was limping around the clubhouse after the game.
The D-backs may have to make another roster move soon, because the team is still unsure if Micah Owings will be able to make his start on Wednesday night. He hurt his gluteus muscle in Friday's 3-1 loss to the Marlins.
The D-backs may have to be a position player short until the status of Owings is known.
"We're still not 100 percent sure on Micah," Melvin said. "We'll know more tomorrow."
Mike Ritter is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.