Estrada (undisclosed) was placed on the minor-league disabled list Wednesday.
Estrada missed the first two weeks of the season with a hip injury, but it's unclear if his current injury is related as specifics remain unclear. The move is backdated to Tuesday, so he'll be eligible to return May 15 if he proves ready. The 22-year-old was hitting just .152/.176/.182 through eight games with Triple-A Scranton/Wilkes-Barre before landing on the DL for a second time this season.