Monasterio is out of the lineup for Monday's game against the Nationals.
Though Marcelo Mayer (forearm) recently joined fellow infielders Trevor Story (sports hernia), Nick Sogard (oblique) and Isiah Kiner-Falefa (forearm) on the injured list, Monasterio hasn't been able to gain a foothold in the Boston lineup. Monasterio will remain on the bench for the fifth game in a row while the Red Sox go with Anthony Seigler and Tsung-Che Cheng as their starters in the middle infield.