Valdespin and Cesar Puello were suspended 50 games for appearing in the Biogenesis clinic on August 5.
Puello is eligible to come off the restricted list on Wednesday.
Sandy Alderson recently told reporters he had not been considering whether to release Valdespin after his suspension, though he is not likely to be added to the team's big league roster before the end of the season.
Josh Edgin has been moved to the 60-day disabled list to make room for Valdespin on the roster.
I was just starting to forget about Valdespin, despite him turning up in my Instagram account every 10 minutes. This is strictly a procedural move, though it does indicate a willingness to let his story play out a bit... wherever that might be. They could have just let him go, but they didn't. Why? In either case, it's hard to imagine someone doing what he did -- melting down in front of the GM and manager, being demoted and suspended -- and finding his way back to their big-league clubhouse, especially considering he hit just .188 while in uniform, but I guess crazier things have happened...