This is a fascinating question, for which there is no one answer; every game is different, but dozens of balls are used .
Juiced ball theory
Juggling balls, or simply balls, are a popular prop used by jugglers, either on their own—usually in sets of three or more—or in combination with other props such as clubs or rings. A juggling ball refers to a juggling object that is roughly spherical in nature.
Beanbags are the most common type of juggling ball. Juggling beanbags are typically constructed with an outer shell made from several pieces of vinyl or imitation leather, and filled with millet, birdseed or other material designed to give the beanbag bulk. Beanbags come in a variety of colors, the most common being "beach" (a combination of Red, Yellow, Blue and Green on each piece of the outer shell), white, black, and other colors that are easily visible. Beanbags are preferred by many jugglers because of their lack of bounce and roll when dropped, the ease with which they are caught, and their reasonable price and availability. Beanbags are generally found in sizes ranging from 2"-3" in diameter, though smaller beanbags with less filling in them are sometimes used by numbers jugglers, who require a smaller and lighter ball to facilitate throwing and catching many balls in the same hand.
The "juiced ball" theory suggested that the baseballs used in Major League Baseball (MLB) during the 1990s and early 2000s were altered in order to increase scoring.
It was claimed that a "juiced" ball bounces off the bat at a higher speed. Johnny Oates observed hits being made off pitches that should not have been elevated.
Zachary Ben Hample (born September 14, 1977, son of Stoo Hample and Naomi Cohen) is an American sports writer and Major League baseball collector. He is best known for having caught more than 7,000 baseballs in the stands at Major League stadiums.
Hample has written three books. The first, How to Snag Major League Baseballs, was published by Simon & Schuster in 1999 when he was a junior at Guilford College. The second, Watching Baseball Smarter, was published by Random House in 2007 and was the 8th best selling American sports book that year. His third book, The Baseball, also published by Random House, was released on March 8, 2011. Hample, a writer for minorleaguebaseball.com from 2005 to 2007, contributed the foreword to Major League Baseball: An Interactive Guide to the World of Sports in 2008 and wrote the introduction for Baseball Scorekeeper in 2011.