“Play ball!” (baseball starting call)

“Play ball!” is what an umpire says to start a baseball game; the crowd also often cheers “play ball!” “Play ball!” is also said to continue a game after a rain delay.
 
“Play ball!” has been cited in print since at least 1885. The national anthem has been played before the start of baseball games since World War II, and a popular joke has it that “Play ball!” is the last line of “The Star-Spangled Banner.”
 
   
Wiktionary: play ball
Verb
play ball (third-person singular simple present plays ball, present participle playing ball, simple past and past participle played ball)
1. (idiomatic) To start anything tumultuous.
2. (idiomatic) To work together; to cooperate.
3. (baseball, softball) An expression used at the beginning of a game of baseball.
 
LA84 Digital Library
30 September 1885, The Sporting Life, pg. 3, col. 1:
MIKE KELLY’S war cry is “play ball.” He’ll have a chance to use it this week.
 
4 October 1885, The Commercial Gazette (Cincinnati, OH), “Base Ball,” pg. 10, col. 2:
A cold rain fell, at one time threatening to stop the game, and the Chicagos, who had obtained a good lead, played to hurry the game, and were met by cries of “Play ball” from the crowd.
 
29 September 1886, Boston (MA) Daily Globe, “Unhappy Anson,” pg. 5, col. 1:
The crowd at this point was one mass of cheering humanity, and the cry of “Play ball” came from all over the field.
 
LA84 Digital Library
6 April 1887, The Sporting Life, “An Umpire’s Chat, pg. 4, col. 3:
Play ball! calls out the umpire,
As he behind the batter stands.
Rats! yell out the crowd on the bleaching boards,
When they use him to mop up the land.
E. S. HENGLE.
 
LA84 Digital Library
20 April 1887, The Sporting Life, pg. 1, col. 5:
“PLAY BALL.”
The Championship Season Opened.
 
LA84 Digital Library
13 July 1887, The Sporting Life, “From the Hub” by Mugwump, pg. 2, col. 2:
There are some stayers on the Boston nine this year and they will be hale and hearty when Cap Kelly calls “play ball” for the last lap in the race.
 
LA84 Digital Library
19 October 1887, The Sporting Life, “From St. Louis” by Joe Pritchard, pg. 2, col. 2:
Just before the gong sounded for “play ball,” Umpires Gartney and Kelly were seen wending their way from the club house toward the grand stand.
 
OCLC WorldCat record
“Play Ball” Stories of the Diamond Field.
Author: Mike Kelly
Publisher: Boston: Press of Emery & Hughes, 1888.
Edition/Format:   Book : English
 
Chronicling America
17 March 1888, Wheeling (WV) Daily Intelligencer, pg. 4, col. 5:
BASE BALL NEWS.
Notes about the Tri-State League and some of the Local Players.
Soon the cry of “play ball” will be heard at the Island Ball Park.
 
LA84 Digital Library
16 May 1908, The Sporting Life, pg. 4, col. 4:
“PLAY BALL,” THE CRY.
E. A. Easton in Harper’s Weekly.
The Small Boy is shrieking. “Play ball!”
Through knot holes he’s peeking. “Play ball!”
With ecstatic features—
Like most rooting creatures,
At this time of year—
He’s fled toward the bleachers,
Half crazy to hear
The praising, the blaming,
The fans all exclaiming,
“Play ball! Play ball!”
 
OCLC WorldCat record
Play ball! / The authentic Little League Baseball guide to basic hitting
Author: John Berzner; Larry Thomas; Tony Richards; Ray Romano; Reggie Smith; All authors
Publisher: Roseland Park, NJ : Inspired Corp. : Peter Pan, 2003.
Series: Play ball.
Edition/Format:   DVD video : Juvenile audience : English