"I hit the corner of the bag and just rolled my ankle," said Jackson. "It's a little sore, but I've rolled my ankle quite a few times in the past. There wasn't much swelling, which is a good thing. I just come in [Monday] and get it re-evaluated and we'll go from there."
Jackson was helped off the field and replaced by Justin Ruggiano in center in the bottom of the third. The 28-year-old Jackson is hitting .242 with two home runs and four RBIs in 25 games. He's scored 11 runs and stolen five bases while filling Seattle's leadoff role for most of the season.
Manager Lloyd McClendon said he'd wait until Monday's tests before making any estimates on how long Jackson might be out, but the center fielder indicated he was hoping he won't need to go on the 15-day disabled list.
"I've done it before and been able to come back from it pretty quick, so hopefully this is one of those times and it's not too bad," he said.
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB as well as his Mariners Musings blog. This story was not subject to the approval of Major League Baseball or its clubs.