Mayer (illness) will start at shortstop and bat seventh Friday against the Mariners, Gabrielle Starr of the Boston Herald reports.
Mayer was originally left out of the starting nine because of an illness, but he now appears to be feeling better and will get the nod at shortstop, replacing Isiah Kiner-Falefa (forearm). Mayer's struggles at the plate have continued into June, as he's slashing .172/.265/.310 across 34 plate appearances since the beginning of the month.