On February 25, 1914, Mattis signed with the major league Pittsburgh Rebels of the newly formed Federal League.
He attended spring training with the Rebels that season in Lynchburg, Virginia.
The Pittsburgh Press described Mattis as having "shoulders like an ox" and that it is likely he would be a star player for Pittsburgh.
The Sporting Life predicted that he would develop into one of the best outfielder is the Federal League.
He made his MLB debut on April 22, against the Brooklyn Tip-Tops.
In his first career MLB plate appearance during that game, he drew a walk.
His first hit came that day, as he got a single, double, and triple in three at-bats.
After two months, Mattis was second in the Federal League in batting average with a .406 clip.
In June, Mattis received a temporary starting job after the Rebels every-day outfielder Davy Jones suffered an injury.
On July 28, Pittsburgh manager Rebel Oakes allowed Mattis to join a semi-professional baseball team in St. Marys, Pennsylvania.
He returned to the Rebels that season on September 11.
On the season with Pittsburgh, he batted .247 with 14 runs scored, 21 hits, four doubles, one triple, eight runs batted in (RBIs), and two stolen bases in 36 games played.
Defensively, Mattis made three errors in 43 total chances in the outfield.
On February 25, 1914, Mattis signed with the major league Pittsburgh Rebels of the newly formed Federal League. He attended spring training with the Rebels that season in Lynchburg, Virginia. The Pittsburgh Press described Mattis as having "shoulders like an ox" and that it is likely he would be a star player for Pittsburgh. The Sporting Life predicted that he would develop into one of the best outfielder is the Federal League. He made his MLB debut on April 22, against the Brooklyn Tip-Tops. In his first career MLB plate appearance during that game, he drew a walk. His first hit came that day, as he got a single, double, and triple in three at-bats. After two months, Mattis was second in the Federal League in batting average with a .406 clip. In June, Mattis received a temporary starting job after the Rebels every-day outfielder Davy Jones suffered an injury. On July 28, Pittsburgh manager Rebel Oakes allowed Mattis to join a semi-professional baseball team in St. Marys, Pennsylvania. He returned to the Rebels that season on September 11. On the season with Pittsburgh, he batted .247 with 14 runs scored, 21 hits, four doubles, one triple, eight runs batted in (RBIs), and two stolen bases in 36 games played. Defensively, Mattis made three errors in 43 total chances in the outfield.
Ralph Mattis