2. David Robertson
Does David Robertson get bonus points for returning at the 2017 trade deadline, somehow becoming the Yankees' most trusted reliever by October, and bringing Tommy Kahnle along with him? Absolutely! He gets the same amount of bonus points that Betances lost by giving up that Hanley Ramirez homer. We recycle bonus points here because we care.
But D-Rob's single season as the Yankees' closer -- which came immediately after Rivera's departure, at an immense pressure cost -- stands on its own merits, too. After striking out 77 in 66.1 innings as one of Mo's primary setup men in 2013 (notice he didn't get the Betances treatment of 90 innings/year?), he found a new gear for his spike curveball in 2014, whiffing a remarkable 96 men in 64.1 innings while recording 39 saves. His 3.08 ERA was a bit misleading, too; Robertson sat at a pristine 0.00 through April, but a wild June outing against the Twins (five runs and three walks in 0.2 innings) blew his numbers up from 2.08 to 4.50. That outing, plus the game where he set up Derek Jeter's Orioles walk-off (of all the dramatic things!) with an implosion, helped push him into territory that probably didn't accurately represent his season.
Robertson's campaign was so good that it earned him a big, fat contract to be the Chicago White Sox closer, which the Yankees were unwilling to match. They probably didn't fill the role in 2015 with anyone nearly as good as -- oh, really?