The D-backs third baseman, who was hit in the head Tuesday by a 95-mph pitch from Washington's Collin Balester, was in Arizona's starting lineup Wednesday night, but was forced to leave the game during a pitching change in the seventh inning.
Reynolds was unavailable for comment following the game and the team said it will continue to monitor his condition.
"He didn't feel 100 percent right, so I think he'll just be day-to-day," Arizona assistant GM Peter Woodfork said following the game. "I don't think it's anything we need to be worried about right now. Doc has already seen him pretty much to the extent that things are OK and clear so we'll see how he comes tomorrow. If he doesn't feel 100 percent, we may go and do some more."
Reynolds had neurological tests done Tuesday night that proved to be normal and he talked his way into the lineup Wednesday.
"I told them I was OK," Reynolds told reporters before Wednesday's game. "I didn't have trouble sleeping, I don't have a headache. I just feel like I got punched in the face."
Reynolds struck out swinging in each of his at-bats and with one out in the top of the seventh, a grounder by Roger Bernandina got by him at third and he seemed to react late to it.
"He felt the ball got by him pretty quickly," Woodfork said.
Two batters later as interim manager Kirk Gibson came to the mound to make a pitching change, Reynolds remarked to second baseman Kelly Johnson and shortstop Stephen Drew that he did not feel right.
"That pitching change he said, 'I'm feeling dizzy,'" Johnson said.
"I looked at him and said, 'What in the world?'" Drew said. "He just looked kind of glazed over. He said he didn't feel right. He asked me and he asked Kelly and I said, 'Get out of here.'"
It was Johnson that first alerted Gibson to the problem and the manager saw for himself when he got to the mound.
"I looked at him and it was obvious something was wrong," Gibson said. "I had to get him out of there for sure. He wasn't right."
Reynolds walked off the field under his own power with assistant athletic trainer Dave Edwards at his side.
"We know Mark, he's going to play through anything," Johnson said. "So when he finally comes over and says something like that, he's not messing around."
Indeed, Reynolds desperately wanted to play Wednesday and though the final decision was made prior to the start of the game, he began lobbying Gibson just two innings after being hit Tuesday night.
"He started last night in the seventh inning," Gibson said.
Reynolds' wife, Kathleen, woke him up every couple of hours Tuesday night as per doctors orders to make sure was conscious.
"It got me off baby duty, so that was good," Reynolds joked, referring to his son Jacob, who his less than a year old.