Trump performs a rendition of "Take Me Out to the Ball Game" on YouTube.

The Washington Nationals take on the Florida Marlins in Nationals Park on Opening Day. Every year, the President of the United States is asked to throw out the first pitch during the Nationals' first home game of the season.

This will be the first season since Donald Trump was elected President in January. The President was invited to throw out the first pitch, as is customary, but he declined.