Reds manager Jerry Narron is cautious about Casey.
"With nine days left in the season, you sure wouldn't want to take a chance where he gets hit in the head," Narron told the paper. "With any head injury, you want to play it safe."
Casey, who has suffered two previous concussions, said Tuesday he was feeling better.
"I'm starting to feel normal again," he told the Enquirer. "It was like I was in a haze."
"I can't really drive the ball," Stewart told the paper. "I'm changing my swing. I'm trying to drive the ball and I can't. This has been a tough year."
He has told manager Ron Gardenhire he's not ready to play.
"He's pretty sore," Gardenhire said. "You saw him swing. Let him rest for a while and see where he's at. If he's shut down for the rest of the year, it's just where it is. If there's a good day and he feels like he can go out there and get some swings in [then, fine]."
To make room on the 40-man roster, Colorado placed Zach Day on
the 60-day disabled list with a broken right thumb.
Day broke his thumb Friday when he stopped a line drive with his
bare hand in a game against Arizona.
Day (1-3) was recalled Sept. 4 from Triple-A Colorado Springs
for a start against the Los Angeles Dodgers. In his next outing, he
went five innings against the Diamondbacks on Sept. 10 in Denver,
giving up six runs, including two homers, in an 8-5 loss.