In Part 4 of our team unit rankings, we have the top 10 outfield combinations in Major League Baseball, based on the input of evaluators. Let's get right to the ranks:

1.Pittsburgh Pirates

Center fielder Andrew McCutchen has created a nice foundation for future Hall of Fame candidacy, finishing in the top five in the National League MVP race in each of the past four seasons, including a first-place finish in 2013. He is one of the best players right now and in the prime of his career. Right fielder Gregory Polanco, 24, took a big step forward in his development last season, fighting through a midseason slump to post a .787 OPS in July and an .880 OPS in August.

Buster's top-10 teams, by position area Starting rotations: Mets easily No. 1

Bullpens: Yankees the clear top unit

Infields: Cubs leap to top spot

Outfields: McCutchen-led Bucs are No. 1

Lineups: Blue Jays power way to No. 1

Defenses: Royals edge D-backs for top spot

Overall teams: How 'bout those Cubbies

But the continued development of Starling Marte into a star-level performer is a big part of why the Pirates' outfield is No. 1 here. Marte worked through injuries to play in 153 games last season and racked up 5.3 WAR, while winning a Gold Glove for his defensive work in left field. Marte "took a step forward last year in the consistent application of his tools offensively and defensively," Pirates GM Neal Huntington wrote in an email. "What is intriguing to think about is that we can help him become even better." As the Pirates attempt to reach the postseason in 2016 for a fourth consecutive season, the outfield will be the team's backbone.