The incident created a somber situation in the Giants' 14-10 win at Marlins Park.
On Saturday, Polanco said he felt better. He doesn't have any concussion symptoms. But as a precaution he was not available for the game against San Francisco, and he will be re-evaluated on Sunday.
"The good sign is, I didn't have any headache," said Polanco, who noted he didn't sleep well. "It's just a little balance. I got hit in the ear. That's how I feel. They told me to lay low today, and see how I feel [Sunday]."
After the game, Giants manager Bruce Bochy called Miami manager Mike Redmond to express his concern.
"I thought that was a class move," Redmond said. "He wanted to make sure he was all right. Obviously, any situation like that is scary for all of us who have been in this game. I hope he is going to be all right."
Marlins trainer Sean Cunningham checked on Polanco. To see if the veteran third baseman had his senses, Cunningham asked what day it was. A simple enough question, but a confusing one to anyone who wears a uniform, because games are played every day, so it took him a few seconds to figure it out.
"The trainer asked me a real tough question," Polanco joked. "It's an answer I don't even know when I am OK. That's the worst question you can ask a baseball player. I was like, 'seriously?' That's why I was laughing a little bit. I was thinking, 'We were off yesterday, so this is Friday.'"
It's not the first time Polanco has been involved in scary moment.
While with the Tigers in 2006, he was hit in the face by an Esteban Loaiza fastball.
"Really scary any time a guy gets hit in the head," Redmond said. "It looks like he's going to be OK. Today will be a day he takes it easy. He's not available for the game. Hopefully, he dodged one there."