Jeff Tesreau was with the New York Giants for all seven of his MLB years (1912-19), but had he not learned the spitball, it is possible that he would not have made it at all.

Tesreau’s first season earned him the ERA Title (1.96), and he was also the leader in H/9 (6.6) and ERA+ (173).  He had another great year in 1913, finishing sixth in MVP voting with his third consecutive H/9 Title (6.6) and a 26-10 record.  Winning 17 decisions against 7 Losses, Tesreau was part of New York's march to winning the Pennant, though they lost to Boston in the World Series.  The following year, the Giants again made it to the Fall Classic, this time losing to the Athletics, with Tesreau going 22-13 (2.17) and again topping the National League in H/9 (7.1).

The spitballer was still good going into 1914, but despite still being well under 30, he was beginning to decline.  After an above-average 1915 (19-15, 2.29 ERA), and decent 1916 (18-14, 2.92 ERA), he slipped in 1917 with a 13-8/3.09 ERA, and was barely used in his third World Series (again, in a losing effort).  He had 12 more Games in 1918, but arm issues prematurely ended his career.

Tesreau had an overall record of 119-72 and an ERA of 2.43.