MLB's one-pitch aces

Kenley Jansen and Tony Cingrani are in Mariano Rivera's class by one measure. USA TODAY Sports

Mariano Rivera will hang up his spikes at the end of the season, putting a close to one of the most incredible pitching careers we have ever seen. By most any barometer, Rivera has achieved outstanding success over the course of his 19 major league seasons. And all of Rivera's pitching success has been attained, remarkably, by him throwing essentially a single pitch: the cut fastball.

Rivera has been a rare exception in employing a one-pitch arsenal. Since the beginning of the 2008 season, just 3.3 percent of pitchers and less than 1 percent of starters -- all but one of them knuckleballers -- have thrown a single pitch more than 80 percent of the time over the course of a season. Clearly, pitchers who can survive the big leagues relying primarily on one pitch are exceedingly rare.

However, this year we have seen two pitchers emerge in the Rivera mold -- non-knuckleballers dominating with the use of just one pitch. Here's how they are doing it.