“He is a big clog in their machine”

A “cog in the machine” is something that helps the machine run. A “clog” (a shoe) in the machine might make the machine stop running. “Clog” is a malaprop for the common “cog” expression.
 
In 1959, Yankees catcher Yogi Berra (1925-2015) learned that Baltimore Orioles catcher Gus Triandos (1930-2013) had been injured. Berra remarked, according to a New York (NY) Times account in 1962, “He’s a big clog in your machine.” Berra was quoted in 1960 about National League Most Valuable Player Dick Groat, “I understand Groat is the bit ‘Clog’ in the Pirate Machin.”
   
In The Yogi Book (1999), Berra said that he made the remark in 1973 about Tony Pérez of the Cincinnati Reds’ Big Red Machine. This “clog” quote probably did occur, but it has not been found in print and is long after Berra made the malaprop famous.
 
   
Wikipedia: Yogi Berra
Lawrence Peter “Yogi” Berra (May 12, 1925 – September 22, 2015) was an American professional baseball catcher, manager, and coach who played 19 seasons in Major League Baseball (MLB) (1946–63, 1965), all but the last for the New York Yankees. An 18-time All-Star and 10-time World Series champion as a player, Berra had a career batting average of .285, while compiling 358 home runs and 1,430 runs batted in. He is one of only five players to win the American League Most Valuable Player Award three times. Widely regarded as one of the greatest catchers in baseball history, Berra was elected to the Baseball Hall of Fame in 1972.
 
The Free Dictionary
a cog in the machine
Someone or something that is functionally necessary but of small significance or importance within a larger operation or organization.
 
7 October 1960, Charleston (WV) Gazette, “Hardman on Sports” by A. L. Hardman, pg. 30, col. 1:
...  latest Yogi Berra-ism: “I understand Groat is the bit ‘Clog’ in the Pirate Machin.” Indeed, Groat could be a “clog” in the Yankee machine before this series is over.
 
Google News Archive
12 June 1962, New York (NY) Times, “Sports of the Times” by Arthur Daley, pg. 43, col. 6:
THREE years ago a foul tip by Jack Harshman crashed off the back of the meat hand of Gus Triandos. The big Baltimore catcher hasn’t been quite the same since. At the start of August that season the power-hitting Triandos has twenty-three homers. In the next two months he got two.
 
Yogi Berra missed him when he was sidelined.
 
“Where’s the big Greek?” asked the talkative Yankee. Then he commiserated with his informant when he heard the news.
 
“Too bad,” added Yogi, a sympathetic malaprop. “He’s a big clog in your machine.”
 
There really was an element of unconscious accuracy in Yogi’s remark. For the next few seasons the burly catcher became a clog in the Baltimore machine as his home run output and batting average faded.
     
Goole Books
Total Baseball
Edited by John Thorn and Pete Palmer, with David Reuther
New York, NY: Warner Books
1989
Pg. ?:
Some Yogi-isms: “He was a big clog in their machine.”
 
Google Books
The Yogi Book:
I Really Didn’t Say Everything I Said!

By Yogi Berra
New York, NY: Workman Publishing
1999
Pg. 113:
While speaking with writers before the l973 playoffs about the Cincinnati “Big Red Machine,” I said: “Tony Perez is a big clog in their machine.”
 
Google Books
Baseball’s Greatest Quotations:
An Illustrated Treasury of Baseball Quotations and Historical Lore (Revised Edition)

By Paul Dickson
New York, NY: HarperCOllins Publishers
2008
Pg. 54:
“He is a big clog in their machine.”
— On Ted Williams (although he allegedly also said it about Tony Perez with the Reds)
 
Google Books
The Wit and Wisdom of Yogi Berra
By Phil Pepe
New York, NY: Diversion Books
2012 (first edition 1974)
Pg. ?:
Farrell once swore he heard Berra say the Orioles would miss the injured Gus Triandos because, “He’s the main clog in their machine,” ...
(Gus Triandos played for the Baltimore Orioles from 1955 to 1962.—ed.)
   
Slate
SEPT. 23 2015 6:17 PM
Yogi Berra Turned Linguistic Vice Into Virtue With His Cockeyed Tautologies
By Ben Zimmer
(...)
Berra is often reputed to have spoken in malapropisms—the accidental substitution of one word for another—but very few of his famous quotations actually fit that description. One of them came in 1973 when, as manager of the Mets, he sized up the opposing Reds in the playoffs and called Cincinnati’s Tony Pérez “a big clog in their machine.”
 
But if all Berra did was mix up words like cog and clog, his Yogi-isms would not be remembered nearly as fondly as they have been.