Soriano's time as the Nationals closer had its ups and downs. During his two year tenure with the Nationals Soriano produced a 3.15 ERA over 128 2/3 innings with a 7.7 K/9 and 2.5 BB/9. Not overall great numbers for the pitcher that is supposed to be the best in the bullpen.
The Rafael Soriano experience wasn't a complete failure. The first half of 2014 was the best Soriano had pitched in years and for that time he was one of the best closers Washington has ever had, but he was in no way worth the $28 million deal Washington signed him to. If the Nationals do decide to bring Soriano back into the fold there will be two key differences this go round. The first is money. It is February 11 and pitchers and catchers report next week. Soriano is sitting out on the market along with K-Rod and Joba Chamberlain. It is unlikely that any of those pitchers gets anything more than a one year deal worth more than $3 million, and it is doubtful that there is a closer's job out there for any of them which would be the second difference.
Whether the Nationals bring back Soriano or not Drew Storen is going to start the season as the closer. What Soriano would provide is depth. He wouldn't cost the Nationals a draft pick or $28 million and he wouldn't be the closer. He would be a reliever signed to a one year deal for a couple million dollars, and in baseball there is no such thing as a bad one year deal. The Nationals bullpen is by no means a weakness, but there are questions with every reliever projected to be a part of it. Drew Storen was good in 2014 and 2012 but very bad in 2013, Casey Janssen is coming off of injury, Matt Thornton is pushing 40, Jerry Blevins can't get out right handed hitters, Craig Stammen has been underrated but most of his success has come as a long reliever, Aaron Barrett struggles with control and against left handed hitters, and finally how will a low strikeout control pitcher like Tanner Roark transition to the bullpen.
That is a lot of players that have question marks attached to them. It's the entire bullpen, and as anyone that watches baseball knows there are questions about most players and during the season some of those questions will be answered in the positive and some the negative. The Nationals already have some bullpen depth with Blake Treinen, Taylor Hill, Taylor Jordan, Sammy Solis, and even A.J. Cole if it comes to that, but more depth is never a bad thing and at a low cost one year deal that is all Soriano would be. What Soriano would really be is the other end of the Jerry Blevins match-up. The one thing Soriano has always been able to do in his career is get right handed hitters out. In his career right handed batters have an OPS of .533 against him compared to .703 for left handers, and even in 2013 when nobody liked him he held right handed batters to a .584 OPS against.
When the inevitable happens and bodies start dropping in the bullpen the Nationals are going to need depth. Adding Soriano pushes Barrett, who otherwise would be the ROOGY, back to the minors along with Treinen and the other extra relievers. In other words it deepens the Nats talent pool. It doesn't necessarily make the bullpen any better as Barrett is just as serviceable as Soriano against right handed batters, but it does give the Nationals another pitcher that can fill that role and one that can step into a larger role in case something happens. The insurance of depth alone makes a couple million dollar deal for one year worth it, and that's not even mentioning how much fun it would be to watch @MASNCommenter literally explode in outrage.