Pitcher C.J. Wilson and four other members of the Texas Rangers were stricken with food poisoning during their trip to Cleveland.
Their conditions have improved, but Washington decided to hold out Wilson from the rest of the series as a precaution.
Wilson had been scheduled to start Wednesday's game but had to be replaced by Colby Lewis, who had been scheduled to pitch Thursday.
"I lost seven pounds in one day," Wilson said. "Not much fun."
Washington had hoped to use Wilson in the series finale Thursday, but changed plans and he will go with left-hander Matt Harrison. Wilson could return to the rotation during a three-game series in New York against the Yankees.
"As weak as C.J. is, there's no reason to push him," Washington said. "With some off days in the schedule, we can shuffle the rotation a bit. We may start Scott Feldman on Friday. We'll have to talk it over."
Feldman had been scheduled to pitch the second game in New York Saturday.
Teagarden was not in Wednesday's lineup, and O'Day was listed as questionable.
Reporter T.R. Sullivan also reports conditioning coach Jose Vazquez and bullpen catcher Josh Frasier also had food poisoning.