Angels manager Mike Scioscia doesn't believe the issue is serious and Guerrero could be back in the lineup Tuesday if his knee feels better.
Guerrero is happy May is over, after hitting just .219 during the month and has just four hits in his last 20 at-bats. His current .249 batting average is the lowest of his career at this point of the season.
But Guerrero has always done well against Seattle, with a career .364 average and 22 homers against the Mariners.
"There have been stretches where he's done what he is doing now," Scioscia said of Guerrero's struggles. "Our offense is a concern and where we've been the last month. And Vlad's a big part of that obviously, but it's not all one guy."
Scioscia also said that Chone Figgins has started running and may be back running the bases later this week. Figgins, currently in his second stint on the disabled list with a strained right hamstring, could go out on a rehab assignment this weekend if everything progresses well.