Solis (shoulder) hit a "roadblock" in his rehab Friday, Dan Kolko of MASN Sports reports.
It's unclear what the setback specifically is, but the Nationals are still hopeful that Solis can return before the end of the season. That being said, having a setback at this point in the season means that the left-hander might not be able to get a rehab assignment in, which could further delay his return. A firmer timetable should become available once his rehab gets back on track, though.