Paul DeJong Is Having an Unexpectedly Great Season

The St. Louis Cardinals needed someone to fill in for the struggling Aledmys Diaz at shortstop earlier this season. Paul DeJong has come out of nowhere to fill that role.

In every baseball season, rookies surprise in ways that can alter organizations for both the present and the future.

In 2014, Jacob deGrom was called up as an afterthought, but the New York Mets fireballer earned himself Rookie of the Year honors. This season, Aaron Judge and Cody Bellinger have hit their way toward being runaway favorites for the award in their respective leagues, as well.

Joining 2017's surprise rookie club is Paul DeJong, who has been a staple of the St. Louis Cardinals offense since getting called up.

Grabbing an Opportunity

DeJong was hardly in the Cardinals' plans this season. He was not a well-known prospect around the league, but the 2015 fourth-round pick out of Illinois State was the organization's 14th-best prospect according to Baseball America. Minor League Baseball -- SB Nation's prospect site -- had him ranked 10th in the Cardinals system. He was not necessarily a non-prospect, but he wasn't on too many radars.

The biggest reason why he was destined to spend the year a Memphis Redbird -- the Cardinals' Triple-A affiliate -- was a dude by the name of Aledmys Diaz. He broke out in a big way last season, slashing .300/369/.510 with a 133 wRC+, numbers that earned him a spot in the All-Star game. It seemed as though DeJong was blocked, unless he changed positions.

Diaz rightfully earned the starting job coming into 2017, and looked like a bright young star for St. Louis. However, that would not last. The Cardinals got off to a sluggish start, and Diaz followed suit, slashing .260/.293/.396 with a lowly 79 wRC+ in 288 plate appearances -- a far cry from his rookie campaign.

The Cardinals wanted to make changes, and they called up DeJong to replace Diaz at shortstop in May. DeJong has ran away with the opportunity, slashing .287/.324/.538 with 22 home runs and a 122 wRC+ in just 380 plate appearances (92 games). He has been a revelation for a St. Louis team that is just three games back in the National League Central entering action on Friday, and two-and-a-half back in the National League Wild Card race.

They are very much in the thick of the playoff race, and DeJong is a key reason why.

A Top Shortstop Bat

DeJong's triple slash and 22 home runs are certainly impressive, and those numbers have helped put him to the top of the qualified shortstops list. The list below shows the top four shortstops in terms of wRC+ this season, with three other stats to compare for good measure.

Player OPS ISO wRC+
Zack Cozart .935 .244 142
Corey Seager .874 .184 132
Paul DeJong .861 .251 122
Francisco Lindor .842 .229 117

DeJong is the third-best offensive bat among qualified starters. His power is what largely sets him apart, as his 22 home runs are tied for second at the position. That kind of power at the position is hard to find, and will be something that makes his bat extremely valuable. However, he is not a qualified shortstop because he hasn't accrued enough plate appearances. He drops to fourth among all shortstops who have played 90-plus games because Carlos Correa missed a bunch of time and has a stellar 141 wRC+ on the season.

Can He Keep it Going?

One of the biggest questions for young baseball players is if the output is sustainable. It is, frankly, hard to tell after just one season.

We can believe the power is legitimate, because he's mashed at every level. He hit 13 home runs in 190 Triple-A at bats before his call-up this year and had 22 in 552 plate appearances at Double-A in 2016. His hard-hit rate is a very good 35.9%, which has helped him sustain a high .354 BABIP. Another plus: DeJong's glove has graded out well: His Defensive Runs Saved is +2 at shortstop, his Ultimate Zone Rating (UZR) is 1.9, and his UZR/150 is 3.7.

On the negative side, DeJong's plate discipline is poor. He has a 4.2% walk rate and swings at a lot of balls outside of the strike zone. His chase rate is 34.9%, which quite a bit above the league average (29.9%). He also has a swinging-strike rate that's higher than league average (10.4%), coming in at 13.8%, and his contact rate sits at 73.8%, which -- you guessed it -- is below the league average of 77.6%.

But considering what we've seen thus far from DeJong -- and taking into account his success at every level -- the Cardinals have once again found value in their minor-league system that's helped them fight for a playoff spot and play meaningful games in September.