X-rays were inconclusive; Reynolds will undergo an MRI on Friday.
"There's no swelling," Reynolds said. "It's like a gnat at a barbecue, just annoying."
It turns out Reynolds -- hitting .283 with 12 home runs, 50 RBIs and a .354 on-base percentage -- has been playing in pain for a couple of weeks. But with shortstop Trevor Story out after undergoing surgery on his left thumb, right fielder Carlos Gonzalez limited by a sprained left ankle and the team going through a rough stretch after pushing into postseason contention, Reynolds played through the issue until Thursday.
"I didn't feel a pop. I didn't feel any more pain than I normally have felt," he said. "But the pain didn't go away as fast as it has in the past. It takes a lot for me to come out of a baseball game, and I couldn't swing."
Thomas Harding has covered the Rockies since 2000, and for MLB.com since 2002. Follow him on Twitter @harding_at_mlb, listen to podcasts and like his Facebook page. This story was not subject to the approval of Major League Baseball or its clubs.