Mastrobuoni will start at shortstop and bat sixth in Wednesday's game against Atlanta, Maddie Lee of the Chicago Sun-Times reports.
With Dansby Swanson (knee) recently going on the injured list and with Nico Hoerner (hamstring) out of the lineup for the second day in a row, Mastrobuoni has been the main beneficiary from a playing-time perspective. He'll draw his fifth start in seven games Wednesday and could continue to see fairly steady playing time in the middle infield even if Hoerner avoids a trip to the IL.