“Can’t hit the broad side of a barn” (baseball saying)

A marksman who “can’t hit the broad side (broadside) of a barn” is a very poor marksman. “You can’t hit the broadside of a barn!” was cited in print in 1852.
 
The idiom was applied to baseball—either for a pitcher who can’t find the strike zone or for a batter who can’t hit the ball. “Neither of the pitchers could hit the broad side of a barn with the sphere” was cited in print in 1895. The expression has also applied to a player’s accuracy in other sports.
 
   
Wikipedia: Barn
Barn idioms
“He couldn’t hit the broad side of a barn” is a popular expression for a person having poor aim when throwing an object or when shooting at something.
 
Dictionary.com
can’t hit the broad side of a barn
Have very poor aim. For example, (...) This hyperbolic term, dating from the mid-1800s, at first denoted poor marksmanship. Around 1900 it also began to be used in baseball, for a pitcher with poor aim.
 
Google Books
June 1852, Yankee Notions, pg. 164, col. 1:
“You can’t hit the broadside of a barn!”
(Referring to the aim of a gun.—ed.)
     
21 November 1853, Milwaukee (WI) Daily Sentinel, pg. 2, col. 4:
An altercation of word ensued—threats were made on both sides—the Irishman threatening to shoto the Norwegian—the Norwegian telling him that he “could not hit the broad side of a barn,” &c. &c., “with his old gun.”
 
18 March 1859, Elkhart (IN) Weekly Review, pg. 1, col. 4:
“You couldn’t hit the broadside of a barn!”
(Referring to the aim of a gun.—ed.)
 
1 January 1874, Cleveland (OH) Leader, pg. 8, col. 3:
She don’t want any one who can’t hit the broadside of a barn in her family.
(Referring to the aim of a gun.—ed.)
 
24 June 1895, Saginaw (MI) Evening News, “City Hall Defeated,” pg. 7, col. 1:
Neither of the pitchers could hit the broad side of a barn with the sphere, to say nothing of tackling it endwise.
 
8 August 1905, Millville (NJ) Evening News, “Eben Holder” by Irving Bacheller, pg. 1, col. 6:
“Willie couldn’t hit the broadside of a barn,” said Tip.
(Referring to the aim of a gun.—ed.)
 
11 April 1908, The Post (Cincinnati, OH), pg. 6, col. 8:
Maybe Ty Cobb can’t hit a ballon these days, and maybe Sam Crawford an’t hit the broadside of a barn, but when the Red pitchers face these fance-smashers Saturday and Sunday they are going to dish up the very best they have in store, nevertheless.
 
Twitter
SAF4SAFF
‏@SAF4SAFF
Sammy Watkins can make all types of highlight catches he wants, it doesn’t hide the fact that EJ Manuel can’t hit the broad side of a barn
6:16 PM - 10 Aug 2014
 
Twitter
Chris jones
‏@cljballa23
Tigers aren’t gonna make the playoffs cause once again they can’t hit the broadside of a barn
10:12 AM - 12 Aug 2014