In the eighth inning, Reynolds chased a foul pop down the left-field line just past the Giants dugout. As he reached the railing, he stretched out to try to make the catch and tumbled headfirst over the railing and fell six feet to the concrete ground.
"I saw the ball, and the wind was pushing it back so I just went for it," said Reynolds. "I almost had it, too. I saw [the railing], I just didn't know there was a 10-foot drop on the other side. If I would have known that, I might not have done that."
The ball went in and out of Reynolds' glove, and shortstop Stephen Drew immediately climbed down into the seating well when he saw Reynolds go down.
D-backs manager Bob Melvin and assistant team trainer Dave Edwards raced out of the first-base dugout to tend to Reynolds.
"When you look at the depth in that area over there, he had a mighty fall," Melvin said. "We were obviously a little concerned running over there."
Reynolds said he didn't hit his head or shoulder, despite what it looked like on the replays, and that the only thing he felt last night was a sore shin. Tuesday morning was a different story.
"When I woke up this morning, my shin hurt and my back hurt," Reynolds said. "It feels like I've got a tennis ball in my shin right now and my back is a little stiff, but I could play if I had to."
But he doesn't have to, and Melvin made that clear in a text message he sent to Reynolds on Tuesday morning that told him he would be getting his first day off.
"He's a little banged up," Melvin said. "I expect him to be in there tomorrow."
Steve Gilbert is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.