Seager is the third Mariners player to deal with the flu bug in recent days, as catcher Mike Zunino dealt with the illness while in New York to start the last road trip and Felix Hernandez lost nine pounds and was under the weather in his start in Houston on May 2.
Seager was hitting .239 with five home runs and 19 RBIs in 33 games going into Friday's action.
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.