Doumit served as designated hitter in Monday's 13-0 loss, going 1-for-3 with a double, and started at catcher on Wednesday after a day off. But he started to feel nauseous during the game and was replaced by Chris Herrmann behind the plate to start the bottom of the fourth inning with right-hander Samuel Deduno on the mound.
Doumit was then examined by a Kansas City doctor at the ballpark, who ruled that Doumit had symptoms consistent with a concussion.
"We're going to evaluate and check him, but the doctor here in Kansas City said he has concussion symptoms so we'll keep an eye, but I'd say there's a high probability he's going on the DL," Antony said.
Doumit, who went 1-for-2 with a single against Royals left-hander Danny Duffy before being replaced, said he hopes to stay off the seven-day DL. He said he's sustained several concussions before and hopes he'll better after an off-day on Thursday. But as Antony noted, it's very likely he'll be placed on the DL.
"I talked to the doctor and he said those are symptoms consistent with a concussion, but I'm not ready to say that yet," Doumit said. "The true test will be Friday when I can go out and do some physical activity."
With Doumit likely headed to the DL, the Twins are now expected to activate outfielder Josh Willingham from the DL in time for Friday's doubleheader against the White Sox. Willingham was scheduled to fly in Friday, but will now leave his rehab assignment with Triple-A Rochester a day earlier than expected to join the team on Thursday in Chicago.
Rhett Bollinger is a reporter for MLB.com. Read his blog, Bollinger Beat, and follow him on Twitter @RhettBollinger. This story was not subject to the approval of Major League Baseball or its clubs.