Foundational building blocks are never easy for NFL teams to find.

Sometimes front offices don't get the right players often enough to ensure sound roster construction. Finding a superb young offensive lineman is great, for example, but if the quarterback he's protecting isn't above-average, it might not lead to success.

The following teams have found their young core pieces (25 or younger) in the proper areas. These outstanding players at premium spots have long careers in front of them and have already shown the flashes necessary to inspire confidence.

That makes overall roster construction over the long-term easier on the front office. 

Paired with the rosters around them, they are in the best positions to succeed over the long term. This doesn't imply the front offices will continue to smartly build around their cores, but they've at least established blueprints for success. 

10. New York Jets

Key Young Core Players: Sam Darnold, Jamal Adams, Quinnen Williams

Things haven't been great for the 2-7 New York Jets this season.

But the future sure looks bright.

Sam Darnold, 22, has shown enough to prove he is worth building around. Provided the second-year quarterback can keep developing at a proper trajectory, he could uplift the talent around him. 

Jamal Adams is a standout 24-year-old safety who leads the team in tackles (52). Quinnen Williams, the third overall pick this year, has 1.5 sacks and three QB hits while flashing plenty of versatility.

Keep in mind the surrounding pieces are beginning to fall into place, with guys like two-time All-Pro running back Le'Veon Bell and four-time Pro Bowl linebacker C.J. Mosley. The project is far from done, but the blueprint looks encouraging.

9. New York Giants

Key Young Core Players: Saquon Barkley, Daniel Jones, Dexter Lawrence

It is hard not to like a core that has a player with the rushing prowess of Saquon Barkley.

The 2018 Offensive Rookie of the Year bullied his way to 1,300-plus yards on the ground and 11 touchdowns last year for a bad New York Giants team. While the 22-year-old running back had one particularly awful showing in Week 10 this season (13 carries for one yard), he would still be on pace for nearly a 1,000-yard campaign if he weren't missing time with a shoulder injury.

Barkley is a nice support for rookie Daniel Jones, who was hindered by a coaching staff unwilling to move on from Eli Manning. The 22-year-old quarterback has shown big upside while completing 63 percent of his passes with 15 touchdowns and eight interceptions despite taking 32 sacks.

Dexter Lawrence, a first-round pick this year, has quietly been a force. The 22-year-old defensive tackle is the highest-graded player on the Giants because of his run defense (sixth at his position), according to Pro Football Focus.

And there are also guys like tight end Evan Engram (25) and guard Will Hernandez (24), not to mention a young wideout not part of the 25-and-under core in Sterling Shepard.

8. Atlanta Falcons

Key Young Core Players: Calvin Ridley, Austin Hooper, Deion Jones

The Atlanta Falcons' 2-7 start shouldn't take away from the budding young core that's flanking quarterback Matt Ryan and six-time Pro Bowl wide receiver Julio Jones.

There's 2018 first-rounder Calvin Ridley, who is averaging 13.1 yards per catch despite sitting third on the team in receiving. The 25-year-old wideout is behind another core piece, tight end Austin Hooper (also 25), who has a team-high six touchdowns and—at 6'4", 254 pounds—gives Ryan with another big matchup nightmare.

Deion Jones, 25, is one of the better modern linebackers in the NFL, hence his four-year, $57 million extension this offseason to lock him up alongside Grady Jarrett.

Things might seem bad now, but the young core looks like it could fuel a quick rebound.

7. Cleveland Browns

Key Young Core Players: Baker Mayfield, David Njoku, Myles Garrett

It's easy to point the finger at Baker Mayfield given the Cleveland Browns' early struggles, but his performances that created hype in the first place should grant him some patience.

No doubt the 24-year-old quarterback has struggled while completing fewer than 60 percent of his passes entering Week 11. But he's not getting much help from a poor offensive line or and the questionable play-calling.

The 6'4" weapon known as David Njoku might be on injured reserve with a broken wrist, but the 23-year-old tight end's arrow continues to point up after he reeled in eight touchdowns over his first two seasons.

And not much needs to be said about Myles Garrett. The 23-year-old defensive end has put up 10 sacks over 10 games plus 24 pressures. He's now suspended indefinitely for his role in a fight at the end of Thursday night's game against Pittsburgh, but he's expected to remain a core building block. 

These three aren't the only promising players, not with talent like 22-year-old cornerback Denzel Ward on the roster. But they could be the biggest reason the Browns have a quick turnaround.

6. Los Angeles Chargers

Key Young Core Players: Mike Williams, Joey Bosa, Derwin James

How can a franchise endure the potential loss of a player like Philip Rivers?

Like this, basically.

The Los Angeles Chargers have a potential top talent at wideout in Mike Williams, 25, who has taken a little longer than expected to emerge but averages a ridiculous 18.9 yards per catch. He will help out the next passer when the 37-year-old quarterback leaves.

Perhaps even more impressive is the defensive side of the ball.

Derwin James, 23, is one of the most promising young safeties and was in Defensive Player of the Year territory last season with 105 combined tackles, 13 pass breakups, 3.5 sacks and three interceptions. Joey Bosa, 24, is in the midst of another dominant performance with 8.5 sacks, 14 hurries and 32 pressures.

While the Chargers seem like they could be headed to a rocky transition soon, the young core should help shoulder the load.

5. Indianapolis Colts

Key Young Core Players: Quenton Nelson, Malik Hooker, Darius Leonard

Quenton Nelson was a brilliant pick by the Indianapolis, even if the prioritization of protecting the quarterback came far too late to salvage the situation with Andrew Luck.

Nelson continues to be one of the league's best players—he has a grade of 89.4 at PFF and has allowed zero sacks, making life easier for quarterback Jacoby Brissett.

There's safety Malik Hooker, a ball hawk with one pick on just six targets, according to PFF, thanks to his rangy, instinctive play on the back end. And Darius Leonard, the reigning Defensive Rookie of the Year, is doing what he does with two interceptions and 60 combined tackles over six games.

4. Houston Texans

Key Young Core Players: Deshaun Watson, Will Fuller V, Laremy Tunsil

It all hinges on Deshaun Watson.

Luckily for the Houston Texans front office, the 24-year-old quarterback has been dynamite over two-and-a-half seasons. This year he ascended even further, completing 70.2 percent of his passes for 2,432 yards with 18 touchdowns against five interceptions.

One of Watson's top weapons, 25-year-old wide receiver Will Fuller V, has scored three times in seven games while averaging 13.2 yards per catch (14.3 for his career). And new arrival Laremy Tunsil, 25, has helped shore up an offensive line, which allowed a league-high 62 sacks in 2018 and was a problem that should have terrified Texans brass.

This doesn't even mention talents like wideout DeAndre Hopkins (27) and safety Justin Reid (22). That should put the rest of the league on notice considering Houston is on track for its second consecutive playoff appearance.

3. New Orleans Saints

Key Young Core Players: Alvin Kamara, Marcus Davenport, Ryan Ramczyk

The New Orleans Saints have managed to walk a superb line between contending now with Drew Brees and laying the foundation for the future.

Said foundation begins with elite tailback Alvin Kamara, 24, who just last year put up 1,500-plus yards with 18 touchdowns from scrimmage. And don't forget Ryan Ramczyk. The 25-year-old offensive tackle is a glue piece up front and has a grade of 85.9 at PFF with zero sacks allowed.

The Saints invested a ton in Marcus Davenport (acquired via trade in April 2018) and are starting to see flashes of a return. The 23-year-old defensive end has three sacks and 21 pressures over nine games.

The age-25 cutoff omits key pieces like Michael Thomas and Cameron Jordan, but were Brees to hang up the cleats, the Saints have a stellar, growing core in place.

2. Kansas City Chiefs

Key Young Core Players: Patrick Mahomes, Tyreek Hill, Mecole Hardman

Patrick Mahomes. The end.

Kidding aside, the 24-year-old has casually thrown 18 touchdowns against one interception over eight games after last year's 50-score performance.

And the Kansas City Chiefs haven't done a bad job of building up the offense around Mahomes. Tyreek Hill, 25, missed four games with a shoulder injury but has five touchdowns and is averaging 16.5 yards per catch through six games. Rookie Mecole Hardman—a 21-year-old speedster himself with a 4.33 40-yard dash—has shown flashes too, with five touchdowns and a league-leading 20.8 yards per reception.

You can't forget Travis Kelce either, even though he's not longer part of the young core in his age-30 season.

An overhaul on defense remains in progress, but it doesn't hurt to have over-25 guys like Frank Clark (26) and Tyrann Mathieu (27) leading the way. 

Given the above, it isn't hard to see why the Chiefs should be in the contention conversation for a long time.

1. Dallas Cowboys

Key Young Core Players: Ezekiel Elliott, Amari Cooper, Jaylon Smith

Arguably the most polarizing team in the NFL is loaded for the future.

Dallas Cowboys running back Ezekiel Elliott is somehow just 24 years old with nearly 5,000 rushing yards and 34 scores along with 1,391 receiving yards and six more touchdowns. Flanking him is Amari Cooper, 25. The  wideout is expected to negotiate an extension after he seemed to single-handedly spur a turnaround with his arrival last year. So far this season, he has 848 yards and seven scores. 

Dallas isn't solely an offensive fireworks show. Jaylon Smith is one of the biggest names to know. The 24-year-old linebacker has 81 combined tackles, four pressures and strong coverage on more than 30 targets.

While Dak Prescott is already 26, assuming he agrees to a contract extension, he has the team in good shape at the quarterback position.

And don't discount a strong offensive line and defenders like DeMarcus Lawrence (27) and Leighton Vander Esch (23), easily rounding out what looks like the NFL's best young core.

Stats courtesy of Pro Football Reference.