While they may be two of the best, where do they fit in with the other coaches in the NBA? Read on to see where Collins and Rivers are ranked along with other head coaches like Erik Spoelstra and Frank Vogel.
F.Y.I.: Paul Silas and Stan Van Gundy are listed with their former teams, even though they are no longer the head coaches.
Paul Silas was fired as the head coach of the Charlotte Bobcats following what is widely considered to be the worst season ever for an NBA team. The Bobcats went 7-59 for the season and Silas took the blame.
Silas was a great player in the NBA during his 16 seasons, but maybe he should have stayed away from coaching. Now Silas will be known as a great player who coached the Charlotte Bobcats to the worst winning percentage in NBA history.
Kaleb Canales took over the Portland Trail Blazers for Nate McMillan when he was fired, and he became the youngest coach in the NBA at just 33 years old.
Canales is simply too inexperienced to be anywhere but near the bottom of this list. Down the road in four or five years, he could be an interesting coaching prospect.
Randy Wittman was thrust in to the head coaching job with the Washington Wizards once Flip Saunders was fired during the 2011-12 season, and Wittman didn't do that great of a job.
He's consistently had lesser talent in all three head coaching stops he's had and the Wizards were probably the most talented team he's ever had. Still, his team was way under .500 and looked lost most of the season.
Keith Smart is more well known for hitting the game-winning shot for the Indiana Hoosiers in the 1987 NCAA Men's Basketball Championship game against the Syracuse Orange then he is for coaching in the NBA.
Smart has thrice been named an interim head coach and most recently he was the interim coach for the Sacramento Kings. He did a lot of good things in Sacramento and, though he finished with a losing record, he could be back on a permanent basis next season.
Dwane Casey was the defensive mind behind the surprise title run by the 2011 Dallas Mavericks and was hired to be the head coach of the Toronto Raptors after that run.
Casey was the head coach of the Minnesota Timberwolves for a season-and-a-half from 2005-2007 and has never had a winning season as an NBA head coach.
Casey needs more time to show how effective he can be as a head coach and the Raptors seem committed to giving him that. Give him around two more years and more talent to work with before passing judgement on his coaching ability.
Mark Jackson had never coached at any level before this season with the Golden State Warriors, but his successful playing career as a cerebral point guard had plenty to do with his hiring. Jackson is third all-time on the NBA's list of career assists with 10,334.
Jackson went 23-43 in his first year of coaching and needs more time to grow. Next season will be key for his coaching legacy, as the Warriors have three solid players in Stephen Curry, David Lee and Andrew Bogut and the team will need to produce.
If Jackson can lead the team to a positive season, his stock will rise considerably.
Kevin McHale is one of the most skilled big men in NBA history, but he hasn't had nearly as much success as a head coach. McHale was hired before the 2011-12 season to coach the Houston Rockets and had a good year until the last couple weeks of the season, during which the team collapsed and missed the playoffs.
McHale has several solid young players on his roster in Houston and could really build them in to a collective unit over the next year or two. Throw in an impact free agent or two and his coaching career could rapidly take off.
Tyrone Corbin was tasked with replacing coaching legend Jerry Sloan, something very few would be willing to do, let alone attempt. Corbin worked hard throughout his first full season as head coach of the Utah Jazz and led the team to a playoff berth.
Corbin is more than capable of coaching at a high level and seems to get the most out of his players. His development as a coach will be key if the Jazz expect to contend for a title anytime in the near future.
Bryon Scott is known for filling the wings with the Showtime Lakers, but the former guard has transitioned nicely in to his role as a head coach. Scott has already been a head coach for over a decade and has two appearances in the NBA Finals (both with the New Jersey Nets).
Coaching stops in New Jersey, New Orleans and Cleveland have yielded four postseason berths for Scott, three of which have gone past the first round. Scott is currently attempting to rebuild the Cleveland Cavaliers in the post-Lebron era, which hasn't proven easy in the two years since James departed for South Beach.
Scott's ability to turn around problem situations, as he did with the Nets and Hornets, will be key for the Cavs as they attempt to rebuild.
Lawrence Frank had a successful stint as the head coach of the New Jersey Nets from 2005-09, including four straight playoff appearances. Frank spent one season as an assistant under Doc Rivers before getting hired before to the 2011-12 season to be the head coach of the Detroit Pistons.
Frank, as expected, did not have a solid year with the Pistons, but he will start putting his mark on the team this offseason. Frank's defensive schemes have proven to work with the Nets and Celtics, so it seems like he needs more defensive-minded players before he can really take off with the Pistons.
Alvin Gentry has been an interim coach on multiple occasions before settling down with the Phoenix Suns and looks to repair a Suns team that has missed the playoffs for two straight seasons.
Gentry took over for Terry Porter during the 2008-09 season and never looked back after getting his shot. Gentry uses his high-octane offensive attack to stymie the opposition and is trying to work more on the defensive side of the ball.
Until he becomes better schooled in the defensive side of the ball, Gentry will continue to be near the bottom of NBA coaches.
Larry Drew took over the head coaching position of the Atlanta Hawks once Mike Woodson was fired following the 2009 postseason and Drew has led the Hawks to two straight playoff appearances.
Drew leans on his cornerstones Joe Johnson, Al Horford and Josh Smith to provide much of the scoring and production. Drew needs to work on developing the bench or else his Hawks will continue to exit early.
Vinny Del Negro had a subpar 114-132 coaching record prior to this breakout 40-26 season for the Los Angeles Clippers en route to their second-round exit to the San Antonio Spurs. Del Negro has an almost too simple offense combined with an average defense, which isn't exactly an amazing combination.
Del Negro certainly has potential to grow as a coach, but he has to get more complex. Running high pick-and-rolls can only get you so far, especially with as poor free-throw shooters that the Clippers have.
Mike Brown has been spoiled to have coached the two best players in the game in his first two coaching stops. Coaches would kill to have the opportunity to have LeBron James and Kobe Bryant be the best player on their first two coaching stops.
In my opinion, the stars he has coached have made him who he is today. They are absolutely the reason why he has a gaudy .658 winning percentage in the regular season (and no rings to show for it) and they have helped him get by with less coaching.
Brown is a solid defensive coach, but his offensive system leaves much to be desired. He really needs to round out his coaching style because his stars won't be there to help him forever.
Monty Williams had a promising first season with the New Orleans Hornets, but the trading of Chris Paul and long injury of Eric Gordon began a rebuilding period that might take a while.
Williams has shown he can lead a team to the playoffs with the right roster, but how soon before he gets the right roster? Maybe not soon enough.
Williams comes from the San Antonio Spurs' coaching staff and brings with him the importance of defense and playing hard. I fully expect Monty Williams to be one of the top young head coaches in the NBA in the next couple years with the Hornets before leaving for a more high-profile job.
Avery Johnson was a true up-and-coming coach with the Dallas Mavericks for a little over three seasons, but shortcomings in the playoffs led to his firing and he moved on to the now Brooklyn Nets.
Johnson has had much less talent the past two years with the Nets, but this upcoming year could be different if everyone returns and is healthy. The Nets could be a solid team if Johnson can install his defensive intensity on his team, as playing with energy and passion can really make a difference on that side of the ball.
Mike Woodson took over as interim head coach of the New York Knicks and did a fine job getting them into the playoffs once Mike D'Antoni abruptly resigned midseason. Woodson is a noted defensive coach, as he helped with defense of the Detroit Pistons during their championship run in 2004.
The Knicks are rumored to be highly interested in bringing back Woodson on a permanent basis, largely because of his ability to get the best out of players, largely on the defensive end.
Scott Skiles is the NBA's leader in assists in one game with 30, but as a head coach, he is much more defensive minded. He worked hard to change the culture in Milwaukee, but when the team traded away center Andrew Bogut, that defense went in to rebuilding mode.
Skiles also likes to run the ball, which should improve now that the backcourt of Monta Ellis and Brandon Jennings is one of the fastest in the league. The thing with Skiles is he's already been with the Bucks for four total seasons, and it might be time for him to produce or get shipped out of town.
I highly doubt that will happen though, as management will have to give this new team a chance to mold together before Skiles could possibly be fired.
Rick Adelman has been an NBA head coach for more then 20 seasons and has had success at almost every coaching stop he has had. He led the Portland Trail Blazers to the NBA Finals twice and coached the Sacramento Kings through one of the best stretches in franchise history from 1998-2006.
Adelman is known for his dynamic scoring offenses and the ability to keep players interested on defense through all the scoring. Adelman is great at molding his strategies around the players he has to work with.
His work with the young players on the Minnesota Timberwolves could lead to the resurgence of a Minnesota franchise that is mired in its losing ways.
Doug Collins was the first overall draft pick in the 1973 NBA draft and a great player for the Philadelphia 76ers before injuries derailed his career.
It made too much sense for the Sixers to bring back the fan favorite Collins as a head coach and he hasn't disappointed, securing a playoff spot in each of his first two seasons. This season's playoff run in particular is significant, as the team upset the No. 1-seeded Chicago Bulls in the first round and currently are battling with the Boston Celtics in the second round.
Collins, like many other NBA coaches, is a tough, defensive-minded coach and has made the most out of his opportunity with the Sixers.
Lionel Hollins knows what it takes to be an NBA champion, as he won a title as a player in 1977 with the Portland Trail Blazers. He uses this experience to lead the emerging Memphis Grizzlies in chase for the first title in franchise history.
His ability to connect with players is key and he certainly has helped players like Michael Conley and Zach Randolph emerge as premier NBA players.
Hollins has been the head coach for a little more then three seasons, but his ability to take the team to consecutive postseason berths has him as a coach on rise.
Erik Spoelstra was thrust in to the national spotlight when the Miami Heat acquired both LeBron James and Chris Bosh before the 2010-11 season and handled the pressure well en route to an NBA Finals appearance.
As a key figure in the youth movement around NBA coaches, Spoelstra looks to secure his first title as a head coach and provide the benchmark for his fellow head coaches under 50 years old.
Luckily for him, Spoelstra has three of the best players in the NBA at his disposal.
Frank Vogel is not nearly as well known as other head coaches in the NBA, but one can't doubt how he has turned around the Indiana Pacers in little over one season. The Pacers have gone from lower-seed playoff team to serious threat under his guidance.
Vogel is the second-youngest NBA head coach and has the chance to develop the talented nucleus of the Pacers in to serious title contenders for years to come. Look for Vogel to really grow in experience and recognition in the next couple years.
Of course, that could change sooner if the upstart Pacers upset the Miami Heat in this year's playoffs.
Rick Carlisle used to be known as the coach of the Indiana Pacers when the famous "Malice at the Palace" brawl broke out. That was, until he led the Dallas Mavericks to the improbable upset over the Miami Heat in the 2011 NBA Finals.
Carlisle immediately went from decent to elite with that surprising run and showed incredible mental toughness throughout against the heavily-favored Heat. Toss in his title as a player with the Boston Celtics in the 1986 playoffs and his resume is building.
Carlisle has only been an NBA coach for 10 seasons, so this is only the beginning of what should be a fruitful career.
Before Stan Van Gundy was relieved of his coaching duties by the Orlando Magic, he led the team during a turbulent season full of drama with Dwight Howard and showed great resolve throughout. It's tough to put the blame on a coach as successful as Van Gundy, but that's what happens in a league driven by its star players.
Van Gundy had a good run with the Magic, but the combination of head-scratching trades made by management and facing superior teams was too much to overcome and, outside of the 2009 postseason, his success in the regular season didn't translate to the playoffs.
Van Gundy is one of the better defensive NBA head coaches and will be a top candidate for vacant coaching jobs this offseason.
George Karl does not have the rings Popovich has, nor does he coach in a marquee market like Los Angeles or New York, but he is easily one of the best coaches in the NBA. Karl has been an NBA head coach for 24 years and is the seventh coach in NBA history to win 1,000 games.
Karl has had several bouts with cancer while coaching but showed considerable toughness in battling back from each bout.
In recent memory, Karl led the Denver Nuggets to a 50-32 record during the 2010-11 season amid distractions from Carmelo Anthony and has helped the team cope without an apparent superstar.
Tom Thibodeau has only been an NBA head coach for two seasons, but they have been two very successful seasons. He won the Coach of the Year award and led the Chicago Bulls to the Eastern Conference finals in this first season.
Thibodeau's defensive smarts are well documented, as he has been a defensive specialist dating back to his 20 years of service as an NBA assistant. As a head coach, he has helped change the dynamic of one of the more prominent NBA franchises and looks to lead the Bulls to reclaim the glory they gained under Michael Jordan.
Thibodeau is the fastest coach in NBA history to 100 wins and tied the record for most wins by a rookie head coach with 62. Tom Thibodeau is right near the top of rising NBA head coaches and will continue up the ranks in the near future.
Scott Brooks was an NBA champion as a player with the Houston Rockets in '94 and appears close to securing a title as a head coach with the Oklahoma City Thunder.
Brooks is one of the younger head coaches in the NBA, but that hasn't stopped him from being one of the best. His Thunder are knocking on the door of NBA contention and Brooks is at the forefront of their recent charge, having developed his young players into bona fide stars.
With all this coming in a mere four years, the future looks extremely bright for Scott Brooks.
Doc Rivers went from All-Star guard with the Atlanta Hawks to NBA champion head coach with the Boston Celtics. Not bad for a guy who got his first NBA head coaching gig only three years after he retired from the NBA in 1996.
Rivers coached the Orlando Magic for a little more than four seasons before becoming the head coach of the Boston Celtics in 2004, the position he has held since. In 2008, Rivers brought Boston its first championship since 1986 and forever placed himself in the hearts of Boston fans.
Rivers is widely responsible for turning around the Celtics and is one of the more recognized defensive coaches in the NBA.
Gregg Popovich is the longest-tenured head coach in the league and the winner of the 2011-12 NBA Coach of the Year. Pop is the model for continued success in the NBA, as he has been the head coach of the San Antonio Spurs for the past 16 seasons.
Not only is Popovich the longest-tenured NBA head coach, he has also guided the Spurs to four NBA championships. His run from 1998-2007 included all four of his championships while the five were won by some guy named Phil Jackson ('98, '00-'02), Larry Brown ('04) and Pat Riley ('06).
Popovich has really learned how to effectively manage his stars as they have grown older, all the while keeping his team's near the top of the standings. When it comes to the gold standard of coaching in the NBA, Gregg Popovich stands at the top.