Once in a while, veteran managers revive it. The Giants took infield occasionally in 2008 and 2013 under Bruce Bochy, and Jim Leyland instituted infield drills before batting practice late in his tenure in Detroit. Molitor, for one, misses it. He took infield even as a designated hitter late in his career because he hated sitting around for almost two hours waiting to play.
Fungo bats are, simply put, a long, skinny, and lightweight baseball bat used for fielding practice. Typically, they are around 34 to 37 inches in length and between 17 and 24 ounces in weight, give or take a couple of ounces. They will also almost always feature a 2 1/4 inch barrel diameter to allow for more control during a swing. As you can tell, fungo bats are longer than a normal baseball bat and much more lightweight in comparison. Most fungo bats are going to be made up of ash wood while there are some maple and bamboo wood fungo bats, some composite wood fungo bats, and very few aluminum alloy fungo bats. Almost all of these designs will be under $100 with very few eclipsing that mark. 

There are many advantages to using a fungo bat. If you are a coach or a parent looking to improve your player's defensive skill set, you're going to want and need a fungo bat. A normal adult wooden baseball bat will weigh around 27-31 ounces, and after a couple of rounds of pop-flys, it is going to feel like you just went through a full-on workout. With the help of a fungo bat, you will be able to hit ground balls and pop flys all day without getting fatigued.  The barrel on a fungo bat will typically be 2 1/4 inches in diameter which greatly helps increase your control over the bat through the hitting zone. While the barrel has a much more thin diameter, it is also much longer in comparison to a normal wood baseball bat. This larger hitting surface and smaller barrel combine to give coaches and parents quick swing speeds with precise accuracy. 
If you have attended a Major League Baseball game in the last 15 years, pregame infield practice, known simply as infield, may be unfamiliar. All but abandoned by the early 2000s, the ritual lives on at the C.W.S. and at college stadiums all over the country. On Monday night, the routine will be repeated before Virginia takes on Vanderbilt in the first game of the finals.

First-base coach Daryl Boston has been working Palka with fungo drills. — Phil Thompson, chicagotribune.com, "Yoan Moncada has untapped power from right side, Rick Renteria says," 23 May 2018 While the Angels took infield before the Texas finale Wednesday, Ohtani stood by the cage with a bat in his hand waiting for BP near where Scioscia was hitting fungo to some infielders. — Stephen Hawkins, chicagotribune.com, "Shohei Ohtani eager for more as Angels balance work for 2-way star," 12 Apr. 2018 And dad liked to take us to Lincoln Park and hit fungos to my twin brother, Javier, and me. — John Hickey, The Mercury News, "Adam and Will Rosales proselytize for baseball," 11 Apr. 2017 Since then, his only baseball activity has been hitting one-handed fungos to teammates in ground ball practice. — Nick Groke, The Denver Post, "Colorado skipper Bud Black faces the Padres with a new perch; Rockies still scanning Desmond, Dahl and Murphy," 10 Apr. 2017
For starters, we should clarify just what we’re talking about when we say fungo bat. Longer, lighter and thinner than a regulation bat (but a larger barrel), a fungo bat is typically 35 to 37 inches long, and weighs between 17 and 22 ounces. As David Allison wrote in the June 1978 edition of Country Journal, “A fungo bat looks to be a cross between a baseball bat and a broomstick.”
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