Every October, there are plenty of veterans that leave their mark on the MLB playoffs, but with this regular season being defined by astounding first-year players, rookies are sure to have an impact on the road to the World Series.

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While last year's Rookie of the Year chase in the National League wasn't much to write home about, the opposite can be said for 2015. First-year players sprouted up throughout the league during the regular season and made their presence felt instantly.

Heading into the 2015 postseason, here are the top rookies to watch for in the NL for each playoff-bound team. To view this in slideshow form, CLICK START at the top right of this page.

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Cardinals: Randal Grichuk

The outfielder is dealing with an elbow injury and may not get a chance to show what he can do in the playoffs, but if he does -- even off the bench -- he can be a catalyst. Grichuk, 24, slashed .276/.328/.552 in 100 games this season and hit 17 homers and 47 RBIs.

Defensively, the rookie has three errors, two assists and is a plus-eight in defensive runs saved, per Fangraphs. He hit just .171 in nine playoff games last season.

Dodgers: Corey Seager

Joc Pederson (25 homers) and Alex Guerrero have been solid, but Seager has burst onto the scene and is the rookie to watch for in Los Angeles. The 21-year-old made his debut on Sept. 3 and though he's only been limited to 25 games, he's still being thrust into the spotlight at shortstop in big games as Los Angeles hunts down home-field advantage.

Seager leads all NL rookies with a .315 batting average and .922 OPS. One knock on the rookie is his five errors in 19 games at shortstop.

Mets: Noah Syndergaard

Michael Conforto is another key rookie for the Amazin's, but for them to beat the Dodgers, the young flamethrower will be a big key. With the Mets mulling using Matt Harvey in Game 3 of the series, the 23-year-old could face the task of trying to best Clayton Kershaw or Zack Greinke in his playoff debut.

Syndergaard (9-7, 3.34) also may be burdened with having to overcome his road woes, as he is 2-5 with a 4.23 ERA away from Citi Field as opposed to 7-2 with a 2.57 mark at home.

Pirates: TBD

It seemed as though Jung Ho Kang was set to make an impact in his first postseason, but his torn MCL has changed any hope of that. With Kang gone, it remains to be seen if any of the Pittsburgh rookies will step up. One possibility is Arquimedes Caminero, who is 4-1 with a 3.72 ERA in 71 games this season.

Cubs: Kris Bryant

Kyle Schwarber, Jorge Soler and Addison Russell may all get a chance to make an impact, but no one will be more exciting to watch than the third baseman. Bryant, 23, leads all rookies with 26 homers and 99 RBIs. His homers are a Cubs rookie record, while his RBIs rank fourth in the NL. He's slashed .279/.369/.495 this season, but his league-leading 195 strikeouts are his only concern.

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