He said his status is day-to-day and that he doesn't plan on missing much time -- if any.
"It feels a little sore right now," Castillo said. "We'll see how it feels tomorrow. I want to play tomorrow."
Castillo sustained the injury when he landed on second base after making the throw to first baseman Carlos Delgado. Once the play ended, Castillo said, he wanted to come out of the game to prevent further injury.
The decision was especially difficult for Castillo because earlier in the game, he hit his second home run in three games. He now has three homers on the season and is quickly approaching his career high of six. He has only 27 career home runs in 13 Major League seasons.
"I am no power hitter, you know," he said, "so I am very lucky right there."
Jon Blau is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.