"We really don't have anybody now that is behind on their ups or pitch count," Showalter said. "We are in a good spot."
This will be Tillman's second unofficial spring start.
Chen pitched with Class A Advanced Frederick and went five-plus innings and allowed one run on two hits and a walk. He threw 76 pitches, 51 strikes.
Gausman went four scoreless innings and gave up two hits with four strikeouts with Class A Delmarva. He threw 56 pitches, 43 strikes.
Brittany Ghiroli is a reporter for MLB.com. Read her blog, Britt's Bird Watch, and follow her on Facebook and Twitter @britt_ghiroli. This story was not subject to the approval of Major League Baseball or its clubs.