Mantiply (shoulder) is scheduled to begin a rehab assignment Tuesday at Double-A Amarillo, Nick Piecoro and Theo Mackie of the Arizona Republic report.
Mantiply, who opened the season on the 15-day injured list with what the team described as "shoulder fatigue," started the return process by throwing to live batters Friday. "The bullpens, the live BPs that he's thrown, everything's ticked up and he's feeling very, very good," manager Torey Lovullo said. The left-hander was projected for a back-end bullpen role before the shoulder issue struck. Since then, Andrew Chafin (two saves) has emerged as the primary lefty to close games. Mantiply is eligible to activated Tuesday, so a return appears imminent.