Cruz's arm will now gain a long rest while he serves a 50-game suspension that Major League Baseball announced on Tuesday.
According to the release, the 32-year-old right-hander tested positive for the use of Stanozolol, a performance-enhancing substance that is in violation of the Minor League Drug Prevention and Treatment Program.
While beginning this season as Double-A Mississippi's closer, Cruz made 30 appearances, posted a 4.76 ERA and allowed opponents a .290 batting average.
In the eight appearances he'd made for Gwinnett, he's worked 8 2/3 scoreless innings and surrendered six hits.
Mark Bowman is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.