Lyles (hamstring) will make a minor-league rehab start Sunday, Jason Mackey of the Pittsburgh Post-Gazette reports.
Lyles completed a four-inning simulated game earlier in the week, but he'll need at least one more tune-up before returning from the injured list. The right-hander is slated to throw six innings or 85 pitches with an undetermined affiliate, and if everything goes as planned, he could be cleared to join the big-league rotation next weekend against the Brewers. In the meantime, Steven Brault is expected to make one more spot start in place of Lyles on Sunday.