Mayer (foot) is out of the lineup for Wednesday's game against the Rockies, Tim Healey of The Boston Globe reports.
Mayer will miss out on a second straight start due to a sore left foot, which stems from him fouling a ball off himself during Monday's series opener. The Red Sox are viewing Mayer as day-to-day, and the infielder could be available off the bench Wednesday if he's noticed some improvement since resting for Tuesday's 5-2 win. Boston will go with Andruw Monasterio at shortstop in the series finale in Colorado.