Joyce has not played since Tuesday, when he left the game in the bottom of the fifth with tightness in the left side of his back.
"It's kind of in a tricky spot; you rotate and feel it," Joyce said. "[It's] just one of those things where you don't want to swing hard and be back to square one."
Andrew Friedman, the Rays' executive vice president of baseball operations, addressed the prospect of Joyce going on the disabled list.
"Can't say no, can't say yes yet," Friedman said. "With Matt we're going to keep playing it out and see how he responds and if he gets significantly better every day. It hasn't happened to date. We'll definitely take it into tomorrow and see how he feels, and then make a decision from there."