Most of the NBA's best backcourt combinations are going to look quite different in 2019-20.

With Russell Westbrook, Kyrie Irving, Kemba Walker, Chris Paul, D'Angelo Russell and Mike Conley all switching teams this offseason, many of the league's best guards will have to adjust to new offenses, coaches and, perhaps most importantly, backcourt mates.

While Stephen Curry and Klay Thompson have set the standard for guard excellence, Thompson will miss most of the season following a torn ACL. Joining him on the injured list are John Wall (Achilles) and Victor Oladipo (ruptured quad), players that would normally join the NBA's best.

There are also questions around positioning that could affect a top-10 list as well. If LeBron James does indeed move to point guard, he and shooting guard Danny Green would make a devastating combo. The same can be said for Patrick Beverley and Paul George/Kawhi Leonard, if the Los Angeles Clippers decide to start one of their superstars at shooting guard instead of having them fill the two forward positions.

To pick the NBA's best guard combos, we took talent, production, prior achievements and fit into account.

With the Association's latest season just weeks from kicking off, here's how the the top 10 backcourts should shake out.

No. 10: Ricky Rubio and Devin Booker, Phoenix Suns

While the wins might not come right away, Booker and Rubio should at least be one of the most entertaining guard combos to watch this season.

Booker has been one of the NBA's best scorers for years, and he's coming off a season in which he scored a career-high 26.6 points on 46.7 percent shooting. He won't turn 23 until late October, which suggests he's still scraping the surface of his ceiling.

Of the top nine scorers in the league, Booker (seventh overall) was the only one who didn't make the playoffs last season. Rubio should help get the 19-win Suns a little closer to the postseason.

Rubio won MVP at the FIBA World Cup, where his Spanish national team took home the gold medal. The 28-year-old point guard averaged 16.4 points and 6.0 assists, outpacing anyone on the American team.

The Suns have long craved a veteran point guard who plays defense and looks to others before settling for his own shot, which Rubio should happily do. Booker has relied on creating his own offense for so long, playing next to a table-setter like Rubio should do wonders for his efficiency.

Look for Booker to take the next step toward superstardom and Rubio to challenge for the league lead in assists with so many young offensive weapons to receive his passes.

No. 9: Kemba Walker and Jaylen Brown, Boston Celtics

Walker and Brown have already gotten a head start on developing chemistry this summer, as both were among the few Americans that agreed to play for Team USA during the FIBA World Cup. The former led the team with 14.4 points and 5.4 assists in 25.4 minutes per game, while the latter chipped in 7.9 points and 4.3 rebounds in 20 minutes.

Walker was named to the All-NBA third team last season after averaging a career-high 25.9 points and 5.6 assists. His scoring will almost certainly drop in Boston, although he's averaged at least 20.9 points per game over each of the past four years. With Kyrie Irving and Al Horford having left in free agency, Walker and third-year forward Jayson Tatum will be tasked with leading the Celtics in scoring.

While he isn't a big-time scorer, Brown should be a nice complement to Walker with his size (6'7", 220 pounds) and defensive ability. Walker is one of the league's smaller guards (6'1", 184 pounds) and figures to only get worse defensively as he enters his 30s in May.

Celtics head coach Brad Stevens could put Marcus Smart in the starting lineup ahead of Brown, but with Terry Rozier gone and no veteran point guard behind Walker, he should prefer to use Smart as a ball-handler off the bench and prioritize the extra offense from Brown in the starting five.

Even though Walker is a slight step down from Irving overall, a big leap from Brown would help solidify this as a top-10 backcourt in the NBA.

No. 8: De'Aaron Fox and Buddy Hield, Sacramento Kings

When one of the league's fastest players pairs with one of its best shooters, you get the Sacramento Kings.

Fox is an absolute blur with the ball and broke out this past season, averaging 17.3 points, 7.3 assists and 1.6 steals while nailing 37.1 percent of his three-pointers. He's also one of the NBA's most underrated dunkers, showcasing his high-flying ability 41 times last season, up from 22 his rookie year.

The 21-year-old Fox is the youngest player featured here, as his play is already nearing All-Star level.

Hield finished seventh in three-point accuracy last season at 42.7 percent, and he led the Kings in scoring with 20.7 points per game. While the 26-year-old is older than most players still on their rookie deals, the Kings are motivated to keep him in Sacramento regardless.

"We are … every day is working and Buddy's a big part of this team, and we'll figure something out down the road," general manager Vlade Divac told Jason Anderson of the Sacramento Bee in reference to a possible Hield extension. "We're working on it and we'll figure out something. Buddy is (a) very important piece to this franchise."

The Kings can offer Hield a five-year extension worth up to a projected $158.1 million before Oct. 21; otherwise, he'll become a restricted free agent next summer. Fox won't be extension-eligible until 2021.

While the pair surprisingly led Sacramento to 39 wins last season, they'll need to have some postseason success before being named one of the NBA's top backcourts.

No. 7: Kyrie Irving and Joe Harris, Brooklyn Nets

In joining Brooklyn, Irving is reunited with former Cleveland Cavaliers teammate Joe Harris.

Harris, 28, is coming off his best season as a pro after leading the NBA with a 47.4 percent shooting mark from three. This figure bumps up to 48.1 percent on catch-and-shoot threes, something he should see a lot of playing next to Irving.

Overall, Harris averaged 13.7 points, 3.8 rebounds and 2.4 assists alongside D'Angelo Russell last season. Spending time next to a ball-dominant guard like Russell should prepare Harris for life with Irving, as he should only get more open looks given Irving's improved ability to break down a defense with his ball-handling.

While Harris isn't a star, he did earn a spot on the USA FIBA World Cup team and should thrive next to Irving as a floor-spacer and low-usage backcourt mate. While Irving struggled in the past playing alongside ball-dominant guards like Dion Waiters, Harris is a catch-and-shoot wing, a la JR Smith, who Irving won a championship with on the 2016 Cavaliers.

Irving, like Harris, is coming off his best statistical season as well.

He led Boston in scoring (23.8 points) and showed off an improved, and more willing, passing game with a career-high 6.9 assists. Irving shot over 40 percent from three for the third straight year, a high number considering he attempted almost as many pull-up threes (3.0) per game as ones off the catch (3.3). 

His catch-and-shoot three-point percentage of 45.4 percent should be aided by Brooklyn's increased team passing (eighth overall compared to Boston's 16th-place ranking), making the Nets one of the best outside shooting backcourts in the NBA.

If Irving can improve his leadership and maintain his passing and defensive levels, he can be a dark-horse MVP candidate.

No. 6: Ben Simmons and Josh Richardson, Philadelphia 76ers

Yet another new backcourt pairing, Simmons and Richardson represent a deadly combination of size, scoring, defense and passing.

The 6'10" Simmons is the league's biggest point guard, a talented ball-handler in a power forward's body with the athleticism of a wing. Having just turned 23 this summer, Simmons has already been an All-Star and is a nightly triple-double threat in just two seasons on the court.

Summer runs have shown an improved jumper, one that he's thus far been afraid to utilize in the NBA. Last season, only six of Simmons' 960 total shot attempts (.006 percent) came from three, and the 2016 No. 1 overall pick has yet to make a three-pointer in his 160 career games. While he can dominate a game in other areas, a reliable jumper would make Simmons one of the best guards in the league.

JJ Redick was the perfect player to offset Simmons' lack of shooting, but Richardson can help cover in more overall areas.

A career 36.8 percent shooter from deep, Richardson has good size (6'6", 200 lbs) to play either wing position and can score from multiple areas. He's not the off-ball player and floor-spacer Redick is, but Richardson is nine years younger and can grow with this Sixers core. He's also a skilled rebounder and passer for his position and is a better ball-handler than Redick.

Richardson is a solid overall player but doesn't possess any one elite skill. If Simmons comes back a capable shooter, this will be one of the most well-rounded backcourts the NBA has to offer.

No. 5: Jamal Murray and Gary Harris, Denver Nuggets

In three years together, the Nuggets have won 57 percent of their games with Murray and Harris, and they earned a No. 2 seed in the Western Conference with 54 wins last season. 

Despite already being this successful, Murray is still just 22, and Harris only recently turned 25. Murray is under contract for the next six seasons; Harris for three. The Nuggets will have both on deals until they each turn 28, at least.

Harris has battled nagging injuries for years but gave us a glimpse of his true potential in 2017-18, when at 23 years old he averaged 17.5 points and shot 39.6 percent from three. After regressing to 12.9 points and shooting 33.9 percent from deep last season, expect Harris to return to his previous year's performance while being a staple on the defensive end.

"It's not just his ability to guard, but his desire to guard and the pride he takes on that end," head coach Mike Malone said of Harris, per Nick Kosmider of The Athletic. "He's a guy that I trust every single night to go out and defend at a high level."

Still, Murray carries the true star potential of the two. It's why Denver handed him a five-year, $170 million extension this offseason.

Murray isn't a traditional floor general and doesn't have to be when sharing the court with Nikola Jokic. While he averaged a career-best 4.8 assists this past season, Denver primarily needs his scoring (18.2 points) and outside shooting. The Nuggets carried a net rating of plus-4.8 in 1,078 total minutes when both Murray and Harris were on the floor last season.

Together, this backcourt seems like a younger version of the Portland Trail Blazers' duo of Damian Lillard and CJ McCollum. Both are already proven winners and lethal scorers, and they continue to fly under the radar.

Given their trajectory, they should settle in as a top-five backcourt for years to come.

No. 4: Mike Conley and Donovan Mitchell, Utah Jazz

Mitchell was already part of a good guard combo last season with Ricky Rubio, as the pair posted a net rating of plus-8.1 together. Still, the Jazz were happy to let Rubio walk and give up two first-round picks and a collection of players for Conley.

Even at age 31, Conley has little to no weaknesses in his game.

While durability has been an issue in the past, he played 70 games last season, giving the Memphis Grizzlies 21.1 points, 3.4 rebounds, 6.4 assists and 1.3 steals per game while making 36.4 percent of his three-pointers. He's a cerebral player who brings Utah 56 games of playoff experience over six years, and he can be both an All-Star-caliber talent and mentor to Mitchell.

At 23, Mitchell has already averaged 22.1 points, 3.9 rebounds and 3.9 assists over his two professional seasons, twice leading Utah to the playoffs.

While Rubio was a good point guard to play next to, the Jazz needed someone who could get his own shot and set the table for others. Someone to take the pressure off Mitchell and not force Rudy Gobert to be the team's second-leading scorer.

Conley, if healthy, can be everything Utah needed and help push the Jazz into the conference finals, if not further.

No. 3: Russell Westbrook and James Harden, Houston Rockets

Besides previously being teammates on an Oklahoma City Thunder team that made the Finals, the pair goes back even farther.

"It's not like me and Russ were just teammates in Oklahoma City for three years. We've known each other since we were 10 years old," Harden revealed to GQ's Alex Shultz. "There's a different kind of relationship and communication that we have, a different type of excitement that we have for each other. We don't really care or pay attention to what other people say or think."

Despite so much individual success, they have never come as close to a championship as they did seven years ago.

It's no secret both are extremely ball-dominant, even if Westbrook has proved he can be the second fiddle to players like Kevin Durant and Paul George.

"It's like, yo, we'll figure it out," Harden told Shultz. "Everything isn't necessarily going to be smooth at first; there are going to be ups and downs, and that's part of an 82-game season. Hopefully by the end of the season, we've caught a rhythm and everybody is on the same page going into the playoffs. That's all you can ask for."

Even after leading the NBA in assists the past two years, it's fair to question if Westbrook can give Harden all the shots he craves. Durant nor George ever reached Harden's numbers from last year, something Chris Paul seemed perfectly fine with most nights.

Even with his high assist numbers, Westbrook has averaged 26.8 points on 21.8 shots the past three seasons. Given Houston averaged 87.4 shot attempts as a team last season, that would leave just 41.1 shots for the rest of the Rockets if Harden and Westbrook continue their combined averages of 46.3.

While this may be the most talented backcourt on paper, fit, turnovers and Westbrook's awful outside shooting (29.0 percent) could hold this duo back.

No. 2: Stephen Curry and D'Angelo Russell, Golden State Warriors

Even with no Klay Thompson, there's no way a Warriors backcourt featuring a healthy Stephen Curry can fall too far. Sharing the court with Shaun Livingston, after all, resulted in a net rating of plus-8.6 last season, numbers that almost doubled that of the Nuggets' Jamal Murray and Gary Harris.

While the fit may be awkward between Curry and Russell at first, the talent is there.

Russell was a first-time All-Star who led the Brooklyn Nets to the playoffs last season behind his 21.1 points and 7.0 assists per game. His high usage percentage (31.9 percent) could force Curry off the ball more and into a spot-up shooter role, something he may actually be more dangerous in.

For Curry, a third MVP trophy could be in sight.

All he did the last time Kevin Durant wasn't in Golden State was average a league-high 30.1 points per game, shoot 45.4 percent from three and lead the Warriors to a record 73 wins. While he may no longer be able to post those same numbers now at age 31, Curry should once again have the ultimate green light with no Durant and Thompson rehabbing for most of the year.

Head coach Steve Kerr has had plenty of time to formulate ways of making his new backcourt pairing work, given the trade for Russell was completed two-and-a-half months ago. Curry is also one of the easiest superstars to share a court with thanks to his unlimited range and the massive attention he commands from defenses.

Russell has never played alongside anyone close to Curry's talent level, and he should enjoy not having to face double-teams or work as hard to generate offense. He's also a capable three-point shooter, connecting on 36.9 percent of his attempts last season.

While Curry and Thompson are the NBA's best backcourt when healthy, Curry-Russell should be great as well. 

No. 1: Damian Lillard and CJ McCollum, Portland Trail Blazers

Talent? Check.

Cohesiveness? Check.

Proven success after six seasons together? Again, check.

With no Curry and Thompson to look up to (for now), the Trail Blazers backcourt can finally stake its claim as the NBA's best.

Coming off a trip to the Western Conference Finals, Lillard and McCollum combined for 46.8 points, 8.6 rebounds and 9.9 assists during the regular season while turning the ball over just 4.2 total times per game. 

In six years together, Portland has never had a losing record, reaching the postseason every time.

Following a 53-win season and the third seed in the West, Lillard almost single-handedly dismantled the Oklahoma City Thunder franchise with a now-iconic shot and pose to end the first round, leading to Paul George requesting a move and a subsequent trade of Westbrook to the Houston Rockets.

In their 16 postseason games, both Lillard and McCollum proved why they deserve to be called the NBA's best. Lillard averaged 26.9 points, 4.8 rebounds, 6.6 assists, 1.7 steals and shot 37.3 percent from deep on nearly 10 attempts per game. McCollum was right behind with 24.7 points, 5.0 rebounds and 3.7 assists, and he drilled 39.3 percent of his three-pointers.

With center Jusuf Nurkic out with a leg injury, no other Blazer averaged more than Enes Kanter's 11.4 points per game. Portland had to be carried by its backcourt to win, and the pair responded.

Greg Swartz covers the NBA for Bleacher Report. Follow him on Twitter. All stats via Basketball Reference unless otherwise noted.