Young has batted only once since straining his left hamstring Sept. 1, but had hoped to return for the start of the weekend series against the AL West-leading Los Angeles Angels.
After hitting off Kevin Millwood in a simulated game Friday afternoon, Young decided he's "just not ready" to play.
Young says he's disappointed but still considers himself "day to day."
He woke up Tuesday and felt ready, and was the designated hitter after testing himself. But he left after one at-bat when he got off-balance on a swing. He says his hamstring has been "pretty tight and stiff" the last couple of days.