"A Marlon-Puig combination for a center fielder," Sandberg said, referring to Marlon Byrd and Yasiel Puig.
Think the Phillies could use somebody like that?
"He looked pretty good," Sandberg said. "Kirby Puckett was the other one who came to mind."
The Phillies could find themselves in a bidding war, if they liked what they saw. The Red Sox, Mariners and others are also having private workouts with Castillo.
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.