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Al-Farouq Aminu and Charlie Villanueva represent a brand of niche players who are good enough at a particular basketball skill to earn playing time in the NBA. However, it's not until those players display at least moderate versatility that they can earn consistent minutes on an elite team.

Both guys have been in and out of the rotation for the Dallas Mavericks this season but have lately grown into more defined roles. Aminu has evolved past the label of a young player with raw potential, while Villanueva is no longer just a garbage-time hero.

But that wasn't the case just a couple of months ago.

Trading away Brandan Wright and Jae Crowder forced Dallas head coach Rick Carlisle to dig deeper into his rotation, but he still relied a ton on Richard Jefferson for frontcourt minutes. Villanueva's defense was such an atrocity that he simply couldn't stay on the floor. Aminu was a virtual zero on the offensive end, and his defense wasn't yet solid enough to make up for it.

As the season has progressed, both players have stayed ready, and their confidence is now soaring. While they might not be highly rated around the league, Aminu and Villanueva are giving Dallas exactly what it needs.

Aminu

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The Mavericks brought Aminu in as an interesting project. They sacrificed a roster spot last summer on the former New Orleans Pelican, who went from being a starter to drawing virtually no interest as a free agent.

Aminu was 23 when he signed with Dallas, an age when players can still develop. The raw physical tools were always there—the long limbs, the freakish athleticism—but he had no finesse to his game. Even though he was a good rebounder, he was a wing who couldn't shoot or add much else offensively.

To witness Aminu's progress this year has been a joy for all Dallas fans. He still can't shoot very well, but he makes up for it in a variety of ways.

He has the highest average plus/minus of any Maverick, and Dallas outscores opponents by 11.3 points per 100 possessions with him on the floor, per NBA.com. That is by far the highest net rating on the roster, with Tyson Chandler being a distant second with 8.3.

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Aminu's defense has evolved the most in the second half of the season, earning him increased playing time. His man-to-man defense isn't as clumsy anymore, and his ability to provide weak-side help has been awe-inspiring.

The way Carlisle has utilized Aminu lately proves that he has the utmost confidence in the young wing. He has guarded just about every type of player imaginable, and it hasn't gone unnoticed among his teammates.

"I mean defensively, he’s almost like (Shawn Marion)," Dirk Nowitzki said, according to Bobby Karalla of Mavs.com. "He can guard 1 through 5, really. He’s probably guarded every position so far. He’s long, he’s quick enough, he’s got unbelievable timing on his shot-blocking, he’s a great rebounder for his size with his long arms. Just his activity is there."

Aminu's development into a lockdown defender and undersized rim protector has been a huge revelation. He has done a terrific job holding his own against bigger bruisers like the Portland Trail Blazers' LaMarcus Aldridge in the low post while also being able to contain explosive point guards around the perimeter.

Take a look at this defensive play:

Aminu recognizes the baseline drive very early and abandons his perimeter matchup to help out Nowitzki. He is a lot more aware as a help defender now. He is capable of sniffing out block opportunities like the one above on a consistent basis, and his timing on weak-side rotations has been close to impeccable in the last couple of weeks.

Karalla provided a great statistical rundown of Aminu's ability to protect the basket:

This season he’s held opponents to just 14-of-38 shooting around the rim, good for 36.8 percent shooting and the 92nd percentile of defenders in the NBA. He blocks 4.0 percent of all opponents’ two-point shots when he’s on the floor, which is the highest mark on the Mavericks of any player with more than two appearances for the team this season.

Even though Aminu is essentially a small forward, his verticality is phenomenal. This has allowed Carlisle to get away with playing super-small lineups with Aminu at the center spot, a proposition that would have seemed preposterous at the beginning of the year. Having a player who can be plugged into virtually any frontcourt position is a great asset.

Offensively, Aminu still has his limitations, and he is shooting just 27.6 percent from deep. But he has shown some positive signs. Even though he isn't a marksman, he is still capable of knocking down the occasional three, and when defenders close out hard he can put the ball on the floor. Here is an example:

Even though Aminu wasn't able to finish the dunk in that play, it was still a terrific example of his physical abilities. Earlier in the season, he didn't have the confidence to put the ball on the floor like that. The fact that he is more comfortable attacking the rim makes him a bigger threat offensively, especially considering that he is often matched up against slower big men.

The most impressive thing is how quickly Aminu has grown into his role once the opportunity presented itself. Even though he is a wing, he has surprisingly good instincts playing at center. Not only is he able to protect the rim, but he is fine with lurking on the baseline on offense and catching lobs, like Chandler.

Aminu still has a lot of limitations offensively but brings more to the table than just a niche skill, which should help him remain in the rotation in the playoffs.

Villanueva

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Villanueva, 30, only just managed to make Dallas' roster and was limited to playing in garbage time early in the year. He was eventually promoted to a heat-check guy Carlisle would throw in for brief stints. To some extent, he still has the same role, but with the added benefit of consistent minutes.

He has never been a good defender, and Villanueva looked awful on that end of the floor earlier in the year. Although he hasn't progressed much, he is no longer as big of a liability and is giving a lot more effort.

Villanueva's primary skill remains his three-point shooting. With a lightning-quick release and a ton of wide-open looks, he is draining a career-high 39.6 percent of his long-range attempts. Instead of simply being thrown into the game for a couple of shot attempts, Villanueva has earned the confidence of his coach and an unconditional permission to shoot, according to Eddie Sefko of The Dallas Morning News:



"He’s a microwave kind of guy," Carlisle said. "That’s one of the great things about him. He can come in and hit a shot. The other night, he wasn’t in the first rotation. Then Houston was making a run. I put him in and we ran a play right there for him and he stepped right in to a three. Boom. He has that skill. He’s always been a guy who can shoot. But he’s worked on his consistency, and it’s shown up in games."

When Villanueva catches fire, all kinds of doors open up for the Mavs offensively. Since his release is so quick, his defender can rarely cheat off him. Take a look at this play:

The Charlotte Hornets' Marvin Williams was sticking to Villanueva like glue throughout the possession. When Dallas ran a pick-and-roll on the left wing, Mo Williams stepped into the lane to help on Chandler's roll. Williams (Marvin) should've in turn helped on Rondo's cut to the basket, but he simply couldn't leave Villanueva.

It's worth noting that two possessions earlier, Williams did rotate away from Villanueva, who proceeded to drain a three as a result.

Even though shooting is his primary attribute, Villanueva has shown an ability to put the ball on the floor when defenders close out hard on him. He also has a couple of post moves in his arsenal, including a soft baby hook he brings out every couple of games.

Villanueva's consistency as a three-point shooter and an overall offensive threat has allowed Carlisle to mix him into all kinds of funky lineups, including the one with Aminu at center.

Both Aminu and Villanueva have their flaws, just like most players coming off the bench around the league. However, considering the fact that they will earn just under $2.3 million combined this season, according to HoopsHype.com, they are certainly providing valuable returns for the modest price.

You can follow me on Twitter: @VytisLasaitis