Taking a look at the 'pen

One thing that I've really taken note of this postseason is how a couple of teams with dominant back ends of their bullpen have really been able to shorten games in their favor and turn a one-run lead after six innings into a fairly comfortable victory. We've seen it time after time with the Royals, who have relied on Kelvin Herrera in the seventh inning, Wade Davis in the eighth and Greg Holland in the ninth. All three bring heat and all three are nearly untouchable, both over the course of the regular season and especially in the playoffs. Herrera and Davis both have a 0.79 ERA over 11 1/3 postseason innings. Holland has a 0.90 ERA in 10 playoff innings, and has converted all seven save opportunities he's been presented. In essence, if Kansas City has any type of lead going to the seventh, the game is pretty much over. The Orioles had similar success with the back end of their bullpen down the stretch, with lefty Andrew Miller, sidearming righty Darren O'Day and closer Zach Britton. They shortened games and put pressure on opponents to push runs across early on. It's not easy to assemble a bullpen that is so dominant in the late innings, of course. The Orioles pieced things together by sliding a former starter in Britton into the closer's role and adding Miller at the trade deadline, while the Royals have seen Herrera put together a career year and Davis (also a former starter) reach a new level while working in relief. It takes talent to assemble a bullpen that can dominate games, and it takes a bit of luck, as well. The Nationals have the makings of a bullpen that can dominate games. Their relief unit finished with a 3.00 ERA in the regular season, fourth-best in the majors. They have weapons from both the right and the left side, but with Rafael Soriano's two-year, $22 million deal coming off the books, general manager Mike Rizzo might have the ability to add to the group he's already got in place. Drew Storen, Tyler Clippard, Matt Thornton and Aaron Barrett all worked in late-inning situations this season, and all four are under contract for 2015. Jerry Blevins will also return. Craig Stammen is still under contractural control. Ross Detwiler has one year of arbitration left. Blake Treinen could even be a candidate to be slotted into the bullpen with his mid-to-upper 90s two-seam fastball. But Rizzo might be inspired to add to his relief corps through free agency or trade. He acquired Blevins in a deal with the A's last winter, and with Soriano's $14 million team option for 2015 almost certainly not being picked up, Rizzo might also have the financial ability to sign another bullpen arm. We'll see how that plays out. The Nats' bullpen was impressive in 2014, but could additional pieces be on the way for 2015?