Unfortunately for Polanco, that stretch was more of an exception than the rule. As a rookie, his hot start fizzled into a .235/.307/.343 batting line. His numbers improved overall last season, but his .256/.320/.381 output still led to a below-average adjusted OPS.
But this, Polanco's second full Major League season, could be the year he takes that highly anticipated next step. That is why Polanco is MLB.com's pick to be the Pirates' breakout player in 2016.
"There were different parts of the season where he was a very, very consistent offensive performer," manager Clint Hurdle said. "The next challenge to be a special player up here is the overall consistency."
Polanco learned a great deal last year about the grind of a 162-game season and how to handle the rigors of playing every day, while still staying fresh enough to be effective in September and, ideally, October.
Polanco knows as well as anybody else that he's capable of more than what he's shown so far. He possesses the raw tools to be a game-changer in every facet of the game: at the plate, where he was a .285 hitter in the Minors; in the outfield, where he recorded 13 assists in 2015; and on the basepaths, where he stole 27 bases last season.
Some fans expected Polanco would march right into the Majors and take his place alongside Andrew McCutchen and Starling Marte, putting up numbers to match them.
That wasn't the case. But Polanco is only 24 years old, young enough to grow and perhaps primed to break out.
"This year is big for me. I want to do what I can do. I want to be more consistent," Polanco said. "This is the year that I want to play how I'd been playing in the Minor Leagues, like a star player. ... I'm preparing for that."
Adam Berry is a reporter for MLB.com. Follow him on Twitter at @adamdberry. This story was not subject to the approval of Major League Baseball or its clubs.