Whether Yankees fans recognize it or not, they are watching one of the most excellent, durable relievers in history.

Tyler Clippard cited flexibility and rigidity for thriving in a job in which bodies are fragile and performance is volatile. Like Mariano Rivera or David Robertson, Clippard recognizes he was blessed with a nimble body – supple fingers, wrists, hips and shoulders.

His inflexibility only appears in his routine – in season and out of season. Clippard says he does not deviate from how he trains, how he diets, how he sleeps. Also, Clippard sticks almost religiously to a fastball/changeup repertoire that is overly familiar to hitters. His velocity hovers only around league average.

“I pride myself [on consistency/durability],” he said. “I have a pretty good sense of self and what makes me good. I stick to that almost to a fault. It works. It just does. Some may watch it and wonder, ‘How does this work?’ But it does.”

Clippard, a starter for the Yankees in the minors, became a Nationals reliever in 2009, and in 41 games (60 1/3 innings) had a 2.69 ERA. In the seven seasons since, he has appeared in at least 69 games every year covering a total of 509 games and 527 1/3 innings, usually serving as a primary setup man, but also a closer at times.

The only other relievers to appear in at least 69 games in seven straight years were lefty specialists who worked much less than Clippard does: Buddy Groom (511 games, 432 2/3 innings) and Mike Myers (532 games, 332 innings), both from 1996-2002. Clippard had an ERA-plus of 142 in that time; Groom was 115 and Myers 118.

Clippard is on pace to appear in 81 games this year and has a 1.37 ERA.