A curtain call doesn’t have to do with an actual play in baseball, but rather the reaction of the fans to a great feat by a player. It is something unique to baseball since fans cannot see the players as well once they go into the dugout while waiting to go back on to the field.
When a player does something extraordinary, such as hit a milestone homerun, fans may continue to cheer once the player is in the dugout. This means they want to see the player again, and he typically abides by going back up the steps and waving to the fans.
Baseball has had its fair share of curtain calls over the last few seasons with the departures of players such as Mariano Rivera, Todd Helton, and Chipper Jones. Derek Jeter is getting plenty of curtain calls this season, as it is his last in the big leagues.
I had the privilege to see a curtain call in person one time. At the old Yankee Stadium, Jason Giambi hit career home run number 300 off of Esteban Yan of the Los Angeles Angels of Anaheim. After a quick descent into the dugout, Giambi came back out to the cheers of the fans and then quickly disappeared again. It was something that was quick and easy to miss, but seeing it in person was pretty cool.
A curtain call is better known to happen at the end of a play. Actors line up once it is over and take a final bow before exiting off of the stage. It is for a job well down and an acknowledgment to the audience. The same applies to baseball as fans salute the performance of the player.