Young injured the shoulder crashing into the wall during Tuesday night's loss to the Pirates. X-rays showed no breaks, and an MRI performed on Wednesday morning showed a deep bruise in the AC joint and a small tear in the ligament there.
In the best-case scenario, Young will be back in 15 days, but at this point there's no way to know.
"I don't think you ever know," general manager Kevin Towers said. "I hate to ever put timelines. All I know is [that] C.Y., when he's ready, is going to want to be back in the lineup."
In fact, Towers said they had to talk Young into going on the DL, a place he's never been since coming to the big leagues in 2006. It wasn't until the doctor said he could worsen the injury that he decided it was the best course of action.
"I don't want to go out there and make it worse, and the next thing you know, you're missing the entire season over it," Young said. "[I'm] just trying to do the right thing and get it healthy."
Infielder Cody Ransom was called up from Triple-A Reno to take Young's place on the roster.
A.J. Pollock, who was called up from Reno on Wednesday when Geoff Blum was placed on the DL, got the start in center in place of Young.
Young has been the D-backs' best hitter this year. He is third in the National League in hitting, with a .410 mark, and is second to the Dodgers' Matt Kemp in home runs (five) and slugging percentage (.897). His loss leaves a big hole in the lineup, especially with right fielder Justin Upton limited by an injured left thumb.
"He was one of the hottest bats in the National League, and to lose him for at least the next couple of weeks will be difficult," Towers said. "But we have to deal with it. Hopefully, we'll be able to get him back sooner rather than later."
"It's one of those deals [where] you have to move on and find a way," manager Kirk Gibson said. "You can't be discouraged. Things happen along the way, and you stand up to that challenge. It's not how we planned it out, but you sign in, and you're either in or out."
Ransom was hitting .294 with a pair of doubles and two home runs for Reno. He appeared in 12 games for the D-backs last year and hit .152.