Butler (knee) was placed on the active/PUP list Monday, Calvin Watkins of the Dallas Morning News reports.
Butler's working his way back after tearing his ACL in December. Dallas is shorthanded at cornerback to begin training camp, as Trevon Diggs (knee), Shavon Revel (knee), Caelen Carson (shoulder) and Kemon Hall (hamstring) are also recovering from injuries.