Gregory Polanco and the Pittsburgh Pirates agreed on a five-year contract extension with two club options that locks in the prime years of the young outfielder, something with which the Pirates have found significant success in recent years, a source with knowledge of the club’s dealings told Yahoo Sports.

Gregory Polanco (AP Photo) More

The deal is believed to guarantee Polanco in the mid-$30 million range, the source said, and should be announced this week. Polanco rejected Pittsburgh’s seven-year, $25 million offer that included three club options before his major league debut in June 2014. In the season and a half since, the 24-year-old right fielder has shown flashes of the brilliance that made him one of baseball’s top prospects before his debut.

Those spells of success have been evened out by deep droughts, including the first half last season, during which he hit just .228/.290/.379. The Pirates believe Polanco’s second-half line of .284/.347/.383 is more indicative of the player he can be, and as they did with Andrew McCutchen and Starling Marte, they’re placing a strong financial bet that Polanco can produce similarly well.

The contract, which will begin in the 2017 season, is similar to the six-year, $31 million deal Marte signed coming off a strong 2013. He has outproduced it with stellar back-to-back years, and the Pirates hold two options on Marte that keep him under club control through the 2021 season. McCutchen signed his deal a year later in service time than Polanco and Marte, and his might be the best of all: six years, $51.5 million with a club option for another $14.5 million, and he has won an MVP award and finished in the top five in the other three seasons.

The biggest question about Polanco is his ability to translate a 6-foot-5, 230-pound frame into more power. Polanco’s aptitude for hitting the ball hard is not in question; in the Pirates’ Opening Day win Sunday, he whacked a single at 112 mph and a double at 109 mph, both elite exit velocities, according to Statcast.

In 652 plate appearances last season, Polanco hit only nine home runs. If he can tap into his power, he’ll make the Pirates’ trend of locking up their outfielders even more successful than it has been already.