The match which De Ligt was watching was behind Miami Marlins and Pittsburgh Pirates in order to wind down after a busy season.
His partner, Annekee Molenaar, uploaded a video to social media in which the Dutch central defender was watching a baseball game.
The rumours over his future continue surrounding De Ligt, who is yet to decide where he will play next season. Now, however, he is on holiday so he will not decide anything for the moment.