Peterson started at shortstop and went 1-for-3 with a run scored in Friday's 6-5 extra-inning loss to Atlanta.
With primary shortstop Geraldo Perdomo (knee) dealing with right knee discomfort -- and expected to undergo an MRI on Saturday -- the lefty-hitting Peterson filled in at shortstop against Atlanta right-hander Spencer Strider. Peterson was eventually pinch hit for by Blaze Alexander in the eighth inning against lefty Aaron Bummer. It's unclear how long Perdomo will be unavailable, and shortstop should be covered by a combination of Peterson (against righties) and Alexander (lefties). Atlanta is throwing left-hander Max Fried on Saturday.