ST. LOUIS — Stability up the middle of the infield really hasn't exactly been a constant for the Cardinals really since the days of Ozzie Smith and Tommy Herr in the 80's.

Herr and Smith started six opening days together as Cardinals. Since then, Fernando Vina and Edgar Renteria are the only combo up the middle to spend at least four opening days together, which in today's era of player movement I guess isn't too bad in terms of longevity.

Names like Adam Kennedy, Delino DeShields, Pete Kozma and Royce Clayton have tried to hang around up the middle but haven't been up to the task.

A new second base/shortstop duo might have something to say not just about the continuity of shortstop and second base heading forward, but the productivity from those positions, too.

In Kolten Wong and Paul DeJong's third season together up the middle, an impressive partnership is budding.

2019 marks Kolten Wong's sixth full season as a Cardinal.

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Before this year, he's shown flashes of excitement both at the plate and in the field but has yet to fully put it together like fans had hoped.

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So far in 2019, Wong looks to be taking on the form of the player we all thought he might be when he was just a prospect from Hawaii.

The glove broke out last year, with Wong emerging as a leading candidate for the NL Gold Glove Award at second base. This year, the bat is catching up.

He's cooled off since setting the world on fire in his first week of 2019, but heading into Monday Wong is still hitting .298/.424/.638 and has seven extra-base-hits in 47 at-bats.

For Wong, a lot of it comes back to his confidence under manager Mike Shildt.

"Double A day one when I got there, he's always been a big fan of mine and believed I was a good player," Wong said of Shildt. "When you have someone who's on your side and believes in you, it helps you believe in yourself."

In Paul DeJong's third season in St. Louis, he has maybe been the Cardinals' most consistent performer 15 games into 2019.

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The shortstop is slashing .306/.368/.597 with 11 extra-base-hits so far this season heading into Monday. He's also moved exclusively to the number three spot in the order this year and has flourished hitting after Paul Goldschmidt and ahead of Marcell Ozuna. 

The highlight reel plays and gold glove love might be commonplace now for Wong, but DeJong is just as impressive at shortstop when you look at the analytics.

Last year, DeJong was sixth in the National League in defensive WAR. Not sixth among shortstops, but sixth among all NL players.

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The duo of DeJong and Wong up the middle is giving the Cardinals stability so far in 2019. It's one thing they really haven't had to worry about yet.

The chemistry between the two is also apparent, and both have mentioned their tight relationship during locker room interviews this season.

So, what might the future hold?

DeJong has a shiny contract that runs through 2023, so he's locked up for a while.

Wong's situation is just a bit less solid. He's signed through 2020 with a team option in 2021. However, if teams continue to dish out extensions at the rate they have been, Wong could very well be in line for an extended stay in St. Louis.

If he continues to play like he has to start 2019 and gel like he has under Mike Shildt, I don't see why the Cardinals wouldn't try to make a longer extension happen.

When asked about the infield's continuity going forward after Matt Carpenter signed his extension last week, Wong expressed excitement.

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"That's what you want, especially on the infield," Wong said. "It's always tough to build that chemistry with your players and to have your core set for the next few years, it's definitely exciting."

If recent returns are to be believed, the double play duo of DeJong and Wong could become a true cornerstone for the next decade of Cardinals baseball.