Moore reached base on an infield single in the eighth inning. But his left foot hit the first-base bag awkwardly, jarring his heel and knee.
He shrugged off the pain and remained in the game against the Rays. But while running to second base after Ichiro Suzuki lined a base hit into the right-field corner, Moore "felt a pop" in his left knee and had to stop at second.
This time, he had to leave the game Seattle eventually lost, 3-2, on a walk-off home run in the bottom of the ninth inning.
"Once I hit the base, I felt it all in my heel," he said. "I felt a little pressure on my knee, but I didn't think anything of it. When Ichi hit that ball down the line, I made my turn around second and that's when I felt a little pop or something."
It was the first hit in three at-bats for Moore, who had hit his first home run of the season in Friday night's series opener.
Manager Don Wakamatsu said Moore would be re-evaluated on Sunday before a roster move is made.
Rob Johnson, who replaced Moore at second and behind the plate, has been bothered by a sore back and had not even taken batting practice the past two days.
Matt Tuiasosopo, who played first base on Saturday, is the emergency third catcher, so when he came to bat in the ninth inning with the go-ahead run on second base, Wakamatsu could not pinch-hit for Tui, who had been 0-for-3 with two strikeouts.
Moore said he thought he would be ready to play again soon.
"I felt a lot better after the X-rays," he said. "Everything is fine. It's just sore right now and hopefully after a couple of days, I'll be able to get back in there."
A possible roster move would be to promote Josh Bard from Triple-A Tacoma, but he's not on the 40-man roster, so a younger, less-experienced receiver might be promoted from Double-A West Tennessee.