The Royals activated Brentz (hamstring) from the 15-day injured list Monday and optioned him to Double-A Northwest Arkansas, Anne Rogers of MLB.com reports.
The hamstring injury that landed Brentz on the IL before the season is no longer an issue, but what is a problem is the 17 walks he issued over six rehab innings. Brentz will stay in the minors to work on ironing out his command problems.