Peters is starting Wednesday's game against the Brewers, Rob Biertempfel of The Athletic reports.
Bryse Wilson was initially slated to take the mound for Pittsburgh on Wednesday, but the 24-year-old was scratched from the start for an unspecified reason. Peters' first five appearances of the season came as a reliever, and he struck out eight in 10.1 scoreless innings while picking up three wins. The southpaw threw 2.2 innings during Sunday's win over the Cubs, so he's unlikely to be able to handle a full workload Wednesday.