Rodriguez was in the original lineup posted by manager Joe Girardi, but removed approximately two hours before the scheduled first pitch against the Mariners at Safeco Field. Rodriguez said the back spasms may be related to being hit on the left elbow by a pitch on Wednesday in New York.
"The whole thing is kind of a one-time deal," Rodriguez said. "I've never been hit like that. I kind of went down and went dizzy a little bit. [I felt] some numbness in my fingers. I didn't feel [the back] until about an hour later."
Rodriguez was hit by the Blue Jays' Shawn Camp in the 11th inning of the Yankees' 4-3 victory on Wednesday, crumpling near the batter's box but remaining in the game to score on Robinson Cano's game-winning single.
He did not play Thursday at Seattle and said he could not be sure if the Yankees would be able to use him Friday, either, needing to speak to Girardi and head trainer Gene Monahan on the subject.
"I haven't tried to swing," Rodriguez said. "Joe and Geno all wanted me to stay off it. I'll talk to Joe and Geno and we'll see how it goes. Hopefully we don't need an at-bat tonight."
Jerry Hairston Jr. was inserted into the Yankees' lineup in Rodriguez's place, batting eighth. Hideki Matsui moved back into the cleanup spot, one night after homering twice and driving in five runs.
Rodriguez said he is looking toward starting on Saturday at Seattle.
"I hope so," Rodriguez said. "I'm going to basically have treatment all game and hopefully be ready to play tomorrow."
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.