Which of the three big Yankees relievers has been the best since 2014?

The Yankees' triumvirate of relief pitchers is as potent as they come. The hype surrounding the trio of Dellin Betances, Andrew Miller and Aroldis Chapman is drawing comparisons to the "Nasty Boys" from the 1990 champion Cincinnati Reds. They also stack up favorably to the team that they were modeled from - the Kansas City Royals, who made back-to-back appearances in the World Series in 2014 and 2015 with Kelvin Herrera and Wade Davis leading the charge and turning into a unit that was practically unbeatable.

While the Yankees' record might not indicate a bevy of successes so far, the numbers would suggest that this is, far and away, the best 1-2-3 combination in Major League Baseball. However, which reliever is the best of the three?

Let's put that question to the test.

The case for: Dellin Betances

Which MLB reliever has the best fWAR since the start of the 2014 season? That would be Dealin' Dellin Betances. His 6.4 fWAR leads all qualified relief pitchers over the course of the last two years entering Monday, and it hasn't been particularly close either. The next highest, coincidentally, happens to be Chapman who checks in with an fWAR of 5.6, which makes for a margin of nearly one full win between the two dominant relievers.

What makes Betances' efforts even more impressive is his heavy amount of innings logged since 2014, when he began to emerge after the Yankees said goodbye to the venerable Mariano Rivera. He has pitched 194.1 innings over this time period, which is easily the most in all of baseball. The next highest mark comes from a pitcher who plays in New York, but in the borough of Queens. Mets reliever Jeurys Familia has amassed 176.2 innings, a near 20-inning difference between the two hurlers.

One could maybe argue that Betances has been taxed and overused in this time period, and they would probably be right. Lately, Joe Girardi has appeared to overmanage his bullpen in situations that did not really require relievers just yet, especially so on back-to-back nights in Arizona and Oakland. The Yankees might have skated by in those situations and that has plenty to do with Betances himself, who has been the first of three imposing pitchers batters have had to face in the late innings.

Still, one has to admire what Betances has brought to the table in this time period, especially consdering the transition he had to make from starter to reliever. Things did not go as planned for him and the prior big trio of he, Manny Banuelos and Andrew Brackman. Nonetheless, it is for both that reason and his overall dominance since 2014 that his case may be strong enough to give him the edge.

The case for: Andrew Miller

No relief pitcher in baseball has a higher K-BB% than Miller's 35.5 percent mark since the start of the 2014 season. As a result, one might expect that his WHIP is rather low, an assertion that would be correct since his 0.81 WHIP over the last two seasons tops Wade Davis' 0.83 mark for the best WHIP in the bigs. His BB/9 is at just 2.40, 32nd in MLB and is vastly superior to the marks both Betances and Chapman have posted.

Several metrics weigh towards Miller at even the most simplest of levels. Entering Monday, opposing batters have hit just .151 against Andrew Miller over the course of the last two seasons. That ranks second in all of baseball and is the best among the Yankees' three ace relievers. It beats out Chapman's mark by a hair, as Chapman's BAA is merely .152, and skates by Dellin's mark of .155. The margin might be razor thin, but the simple truth is that it's a tally in the win column for him.

The case for: Aroldis Chapman

No relief pitcher since the start of the 2014 season has had a higher K/9 than Chapman's gaudy mark of 16.33. Interestingly enough, it's Chapman, Miller and Betances, in that order, who are at the top of the majors in that statistic, which is a primary reason why this bullpen has gotten so many rave reviews. Chapman's walk rate might be a lofty 4.10 but his K/BB is still relatively low - 3.98 - and he keeps home runs to a minimum with a mark of 0.28 with regards to HR/9.

Furthermore, Chapman's FIP of 1.44 is the best in the bigs in this time span, greater than that of Miller, Davis, Betances, Kenley Jansen, and other top quality relief pitchers. He has, in a word, been unhittable, no matter how you slice it. It helps when one has such a high velocity as well. Chapman's fastball has never been marked at less than 98 miles per hour since entering the league, and he had an average mark of 100.2 (!) back in 2014. When you're throwing faster than damn near everyone, there's a good chance you're going to be unhittable if you can master it. That's exactly what's happened with Chapman.

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So who is the best? Now, that question is for you to decide.