Pena (illness) was placed on High-A Wisconsin's 7-day injured list Friday, Adam McCalvy of MLB.com reports.
Pena has been recovering from an incident in late April, when he had to go to the hospital after becoming overheated in the dugout. Per McCalvy, Pena has progressed enough in his recovery to resume baseball activities, and his move to the 7-day IL allows him to embark on a rehab assignment in the Arizona Complex League.