D-backs manager Kirk Gibson said the injury is similar to the one suffered by shortstop Didi Gregorius over the winter. Gregorius was shut down after his injury and once he resumed throwing in Spring Training, he felt fine and experienced no setbacks.
Reynolds had been one of the D-backs most consistent relievers this year before injuring his elbow. He was placed on the 15-day disabled list Monday and left-hander Joe Paterson was called up from Triple-A Reno to take his place on the roster.
"Injuries can never be an excuse for us," Gibson said. "It's a blow. There's other guys that are prepared for the opportunity to be part of the team in this capacity and it opens up that avenue for them. We need to get him back healthy and hopefully he can come back and contribute before this year gets over."
Reynolds, who was acquired from the Rockies during the offseason, had a 1.98 ERA and two saves in 30 appearances this year.