By Bruce Levine–

WASHINGTON D.C. (CBS) — The Cubs’ 25-man roster for the National League Division Series was structured based on the proper matchups against a talented Nationals lineup and pitching staff and right-hander Jake Arrieta’s health.

The Cubs left right-handed reliever Hector Rondon off the roster for the best-of-five series that starts Friday night because of the need to carry an extra long man and a third left-handed reliever against a Nationals team that boasts lefty-swinging stars in Bryce Harper and Daniel Murphy.

With Arrieta still not 100 percent after straining his right hamstring in early September, the Cubs chose to include No. 5 starter John Lackey on the roster. He’ll be in a wait-and-see mode and serve as a safety net. Should a starter struggle early in a game, he could get the call out of the bullpen. And should Arrieta have trouble with his hamstring before or in a potential Game 4, Lackey would be in line to get the ball.

Despite many struggles in the past two months, Justin Wilson was included on the NLDS roster because of the Cubs’ desire for a third lefty reliever to match up against Harper and Murphy. If left-hander Mike Montgomery has to be used earlier in a game to put out a fire, Wilson will give the Cubs a second lefty along with Brian Duensing to match up in the late innings.

The inclusion of outfielder Leonys Martin was the odd choice by the Cubs, but he has speed and is excellent defensively. The thought process was that he could serve as a pinch-runner late in the game to help manufacture a run against a tough pitching staff.

The second catcher choice was more difficult for the Cubs than many thought. Alex Avila got the nod based on his postseason experience and lefty bat. Rene Rivera was left off the roster, though he has a better arm and more power than Avila. Either way, the second catcher isn’t going to play unless Willson Contreras gets injured or a game goes extremely long.

In the case of injury in a series to anyone on the 25-man roster, the league allows a replacement. The catch is that if the player is replaced on the 25-man roster, he must miss the next round of the playoffs.

Bruce Levine covers the Cubs and White Sox for 670 The Score and Follow him on Twitter @MLBBruceLevine.