MLB's top 5 bullpen combos after Kimbrel trade

Boston Red Sox president Dave Dombrowski demonstrated the importance teams are placing on strong bullpens after shipping four prospects to the San Diego Padres in exchange for closer Craig Kimbrel on Friday.

The road to the postseason has been driven through the bullpen, as the Kansas City Royals are reigning World Series champions, while the St. Louis Cardinals and Pittsburgh Pirates finished the season with a league-best 100 and 98 wins respectively. Those three teams finished with the majors' three lowest bullpen ERAs and are headlined by a strong duo at the back of the bullpen.

Dombrowski understands a strong bullpen presence is necessary to be successful, and he now possesses two imperative pieces.

With that being said, here are MLB's top one-two bullpen punches:

Melancon-Watson, Pirates

Mark Melancon continues to thrive in Pittsburgh, as the closer converted a league-leading 51 saves last season. While neither Melancon nor setup man Tony Watson boast big strikeout numbers, the duo posted a sparking 0.94 WHIP over 152 innings. The pair were almost automatic, as the Pirates were 79-1 when leading after the seventh inning.

Kimbrel-Uehara, Red Sox

Koji Uehara will concede his throne at the back end of the Red Sox bullpen following the acquisition of Kimbrel - a four-time All-Star - on Friday, though the move gives Boston's beleaguered relief core a massive jolt. Named closer by default in 2013 following a pair of injuries, Uehara owns a 1.86 ERA and 229 strikeouts over 179 innings the past three seasons. Though Kimbrel got off to an uncharacteristically poor start in 2015, the flamethrower still managed a 2.58 ERA and 1.05 WHIP and leads all relievers in WAR (12.9), saves (225), and strikeouts (563) since 2010.

Rosenthal-Siegrist, Cardinals

Trevor Rosenthal, 25, and Kevin Siegrist, 26, form one of baseball's most potent - and youngest - relief tandems. Thrust into the setup role following an injury to Jordan Walden, Siegrist was leaned on heavily, striking out 90 in a league-leading 81 appearances. Rosenthal continued to dominate during his second season as the Cardinals closer, setting the franchise record with 48 saves.

Davis-Herrera, Royals

The Royals bullpen not only absorbed the loss of closer Greg Holland in late September, but they arguably improved. Wade Davis continues to be one of the best relievers in the majors since his transition from a starter in 2014, posting a 0.94 ERA over 67 1/3 innings last season, in addition to 10 2/3 scoreless postseason innings. Flamethrower Kelvin Herrera, who features the second highest fastball among relievers, wrapped up his season with a career-low 1.12 WHIP.

Miller-Betances, Yankees

General manager Brian Cashman opted not to retain then-closer David Robertson last offseason, instead opting to sign Andrew Miller to a four-year, $36-million deal. Already armed with Dellin Betances, the move gave New York the majors' most feared relief tandem. The Yankees were 73-2 when taking a lead into the eighth inning, while Miller and Betances were two of only three relievers to eclipse the century mark in strikeouts.