Rodriguez doubled and scored in the top of the first as the Mariners rolled to a 9-5 victory. The center fielder walked off the field slowly with a trainer in the bottom of the inning.
Rodriguez recently missed three games with a lower back issue.
"Concerning,'' Mariners manager Scott Servais said. "It's the same area in the low back. He'll get work up [Friday] when we get to Kansas City, get an MRI and pictures of that.''
"When Julio went down, we just kind of picked each other up and grinded through it, came out on top,'' Kelenic said. "That was the biggest thing.''
Rodriguez recently missed three games in Anaheim with a lower back issue. The front-runner for AL Rookie of the Year is batting .280 with 27 homers and 73 RBI in 129 games.
With the win, Seattle avoided a three-game sweep against the last-place Athletics.