Musgrove (shoulder) will throw three bullpen sessions before heading out on a rehab assignment, Rob Biertempfel of The Athletic Pittsburgh reports.
The right-hander is expected to throw 25-30 fastballs in his next bullpen session Thursday. Musgrove still needs to be built back up to a starter's workload, so it seems like he won't be back in the Pirates' rotation until late May or early June.