The following is an excerpt from The Low Self-Esteem Club: Baseball's Most Unflattering Nicknames by C. Terry Walters
James Leslie Vaughn was a Texas-size pitcher worthy of the Lone Star state’s reputation for bigger-than-life everything. Standing on the raised mound, the 6’ 4” 215 pound lefty must have intimidated many of the small-framed players of the dead ball era. Later in his career he was reported to have ballooned to almost 300 pounds. But Vaughn was not named because of his weight or likeness to a hippopotamus, but for the ungainly way he carried his frame when he ran. 
One might think that a name like Hippo could fall into the cruel category. There is evidence that Vaughn more than acquiesced to his nickname. In a call to the Chicago police in October of 1921, his wife reported that Vaughn had been missing for several days and his three-year-old son, Little Hippo, was crying for his daddy. Vaughn was not only content be called Hippo, he passed on the nickname to his little boy. 
Vaughn debuted with the New York Highlanders (Yankees) in 1908 but could not stick with the team. After that false start, he was back with the Highlanders in 1910 and distinguished himself with a 13-11 record and sparkling 1.83 ERA.
After a few uneventful seasons in New York and Washington, he was purchased by the
Chicago Cubs in 1913. One year later his career took wings and Hippo was flying high. From 1915 through 1921 he averaged over twenty wins per seasons. In 1918, his league-leading twenty-two wins helped send the Cubs to the World Series against the Boston Red Sox. The Cubs, of course, lost to the Sox and a pitcher named Babe Ruth.
In 1917, pitching for the Cubs, Vaughn and Cincinnati’s Fred Toney tangled in a pitching duel for all time. After nine innings, both pitchers had not yielded a hit. In the top of the tenth, Vaughn retired the first batter before Larry Kopf singled. After an error and a stolen base. Jim Thorpe walked to the plate. Thorpe dropped a swing bunt down the third base line that Vaughn fielded. “I knew the minute it was hit that I couldn’t get Thorpe at first, “ reported Vaughn, “He was as fast as a race horse.” Vaughn threw to the plate but failed to get Kopf.  Toney retired the Cubs in the last of the tenth and preserved his no-hitter. The game was known as a double no hitter and was the defining moment of Vaughn’s life.
Vaughn, himself, proclaims the Toney matchup as the high point of his career. Even though 3,500 fans attended the game, Vaughn recalls over 10,00 people who claimed they were there that day. Vaughn refers to the game-winning batter as Indian Jim Thorpe, a comment that underscores the racial and ethnic stereo typing of that era.  Only Thorpe’s worldwide reputation spared him from becoming Chief Thorpe in the baseball world.
His major league career ended in 1921 amidst a flurry of mystery and drama. On July 9, he took the mound in the Polo Grounds with a dismal 3-10 record. In the fourth inning he surrendered a grand slam homer to Giants catcher Frank Snyder. Insult then joined injury as pitcher Phil Douglas followed with his first career homerun. Manager Johnny Evers then gave Vaughn the hook. Two days later, Vaughn was nowhere to be found and the Cubs announced that Vaughn would be suspended if and when he returned to the team. 
By early August, Vaughn was still AWOL and the Cubs reportedly suspended him for what the Chicago Tribune described as “failure to keep in fighting trim.” Furthermore, Vaughn had allegedly signed a contract to play for the Beloit Fairies, a non-affiliated team owned by the Fairbanks Morse Engine Company who manufactured everything from typewriters to locomotives. A Hippo becoming a member of the Fairies just does not present a pleasant visual image.
When Evers was suddenly fired as manager, his replacement Bill Killefer and Cubs president Bill Veeck Sr. agreed to reinstate Vaughn if Commissioner Landis agreed. Landis, however, decided to suspend Vaughn for the rest of the season for signing the contract with Beloit. Vaughn never returned to the Cubs or the major leagues again. Various reports list various reasons for his departure. He was fed up with Evers. He had a sore arm. His weight had finally affected his performance. Vaughn kept the reason or reasons to himself. His new career in semi-pro ball lasted another sixteen years and he finally hung up the cleats at age 49. 
Vaughn died in Chicago in 1966. At the time of his death, he still had bragging rights as the Cubs all-time leader in wins by a left-handed pitcher with 151 victories. Larry French was a distant second at 95. As of this writing, that distinction still belongs to the man called Hippo.
1. Tales From the Cubs Dugout by Pete Cava p. 239
2. Hippo Vaughn by Jan Finkel – the Baseball Biography Project BioProjSABR.org
3. Tales From the Cubs Dugout by Pete Cava p. 239
4. Jim Thorpe, a comment that underscores the racial and ethnic stereo typing of that era. [My greatest day in baseball; forty-seven dramatic stories by forty-seven stars by John P. Carmichael and Jerome Holtzman
5. Hippo Vaughn by Jan Finkel – the Baseball Biography Project BioProjSABR.org