Still, manager Rick Renteria said he wants to see both Baker and Castillo behind the plate moving forward.
"It's where we believe that the combination of both [Castillo] and [Baker] fit," Renteria said. "We obviously want both of them to be able to receive. We want [Castillo] to be in there. And with [Castillo] coming off of that DL stint, he's been playing pretty consistently. So we're trying to get him into shape. He's another guy who likes playing every single day, just as all those guys do. So we'll just work it through and see how it continues to develop."
Baker was back in the starting lineup on Sunday for the second time in the past three games to give Castillo the day off following the Cubs' 13-0 loss to the Nationals on Saturday.
Daniel Popper is an associate reporter for MLB.com. He also can be found on Twitter @danielrpopper. Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.