» December 15, 1905:
Boston (NL) continues trading, sending C Pat Moran to the Cubs for C Jack O'Neill and P Big Jeff Pfeffer.
» May 8, 1907: Frank Pfeffer of the Boston Doves pitches a 6-0 no-hitter against the Reds. He will be known as "Big Jeff" until his younger, and bigger, brother Ed "Jeff" Pfeffer becomes a star hurler for Brooklyn in 1913.
» February 11, 1911: The Cubs acquire 2B Dave Shean from Boston for 3B Scotty Ingerton and righty Big Jeff Pfeffer. The is the 2nd time that Boston has traded with the Cubs for Big Jeff.
» September 30, 1914: The Dodgers stop Grover Cleveland Alexander's win streak at nine games, defeating the Phils, 2–1, behind Jeff Pfeffer. Alex is done in by three Phillie errors.
» June 17, 1915: George "Zip" Zabel comes out of the Cubs bullpen with two outs in the first and winds up with a 4–3 nineteen-inning 4–3 win over Brooklyn, the longest relief job ever. Brooklyn starter Jeff Pfeffer scatters 15 hits as he labors 18 1/3 innings, only to lose on an errant throw by 2B George Cutshaw.
» July 29, 1915: At 41, Honus Wagner becomes the oldest player in this century to hit a grand slam when he connects in Pittsburgh in the drizzling rain. It is inside the park against Jeff Pfeffer of Brooklyn in an 8–2 win. The record will stand until Tony Perez hits a grand slam on May 13, 1985, one day short of his 43rd birthday.
» September 9, 1915: Boston's Lefty Tyler allows just one Brooklyn hit, but loses 1–0. Jeff Pfeffer is nearly as perfect, allowing two hits for the win. Brooklyn scores the lone run on a walk by Hy Myers, Gus Getz's single, a double steal, and a sac fly.
» May 14, 1916: The Cardinals rookie Rogers Hornsby hits his first home run, off Brooklyn's Jeff Pfeffer. It is a bounce home run (legal till 1931) that lands behind 3B and skips into the stands at Robison Field in St. Louis.
» October 10, 1916: In Game Three, Larry Gardener's 7th inning home run over the RF fence at Brooklyn brings the Sox within a run 4–3, but Jeff Pfeffer, in relief of Jack Coombs, shuts them down. Carl Mays takes the loss. Charlie Ebbets becomes the first owner to raise the price of World Series grandstand seats to $5—up from $3.
» August 25, 1917: Behind Jeff Pfeffer and Rube Marquard, the Dodgers apply a doubleheader whitewash to the Cardinals, winning 12–0 and 4–0. Brooklyn's Hy Myers is thrown out three times trying to steal in one game by the Cards, the 2nd player this year to be thrown out three times in a game. Not till Rodney Scott, in 1979, will another NL runner be caught stealing three times.
» September 4, 1917: The Phillies Joe Oeschger and Brooklyn's Jeff Pfeffer face off to a 14-inning scoreless tie. Pfeffer gives up just three hits, while Oeschger allows just 6.
» March 25, 1920: In a spring training match between the Yankees and Dodgers, a sweeping inside curve ball by Brooklyn's Little Jeff Pfeffer beans Chick Fewster striking the Yankee SS behind the ear and flattening him. Fewster revives 10 minutes later but soon loses the ability to speak. Taken to the hospital with a skull fracture and a blood clot on his brain, Fewster will recover slowly and return to play in mid-season.