Regardless of how Doc Rivers' coaching tenure with the Celtics ends, it will be remembered as a success. The man brought a championship to Boston by getting three aging superstars to buy into Ubuntu, a concept that seemed cheesy to anyone outside the team but proved to be the perfect motivator for his players.

Rivers should be on a short list of candidates to coach the 2016 U.S. Olympic team. It's the perfect post for Rivers, who is at his best coaching superstars. Rivers takes talent and creates chemistry. If this year's Lakers are any indication, that is an underrated skill in the NBA coaching ranks.

That being said, Rivers is no longer the best coach for the Celtics moving forward. Rajon Rondo's injury Sunday marked a definitive shift in the long-term vision for the team. A team that sits at 22-23 was never a championship contender, but with a second-half push, the ceiling was another run to the Eastern Conference finals, where LeBron James and the Heat will be waiting.

Without Rondo, the Celtics' ceiling is a bottom-four seed in the Eastern Conference playoffs. They currently are 11-16 against teams with records of .500 or better. They are savvy enough to beat up on the bottom-feeders of the NBA, but they are no longer athletic enough to compete with the upper-echelon teams on a nightly basis.

The prognosis for Rondo is unclear after this season. It is possible he could return to the court for the start of next season in late October, although Bulls guard Derrick Rose suffered a similar injury last April and has yet to return nine months later.

A more applicable injury comparison for Rondo might be Ricky Rubio, who possesses many of the same strengths and weaknesses as the Celtics guard. Rubio has special court vision and passing skills like Rondo, but also like Rondo, his jump shot is lacking and he is most dangerous as a scorer around the basket. Rubio tore his ACL last March and returned in December -- a nine-month recovery period. Rubio has struggled mightily in his return to the court this season.

Rubio's shooting percentage has dropped from 35.7 percent to 23.1. Last year, Rubio had success penetrating; he made 1.7 shots per game inside of 15 feet. This year, he has been unable to get to the rim on his dribble-drives. He's made only 0.4 shots per game inside of 15 feet, hence the low shooting percentage.

If Rondo's shooting percentage dips in similar fashion next season due to a lack of mobility, the Celtics' championship chances would not improve from this season. Rondo will not be as dangerous as a passer if defenders don't have to account for his speed to the basket, and his shooting percentage will plummet if defenders aren't forced to grant him space to operate. As a result, Celtics president of basketball operations Danny Ainge is best served going into rebuilding mode now. He must think long term (3-4 years down the road) as the Celtics won't be a championship contender until 2015 at the earliest. We've seen Pierce lose more than a step in the last few seasons. He does not figure to be a championship-caliber player in 2015 unless he accepts a greatly reduced role. Easing his players into that transition has not been a skill of Rivers'.

Despite Rivers' strengths as a motivator of top talent, he has not proven especially effective molding young talent. In the three years before Rivers was hired as Celtics coach prior to the 2004-05 season, the Celtics logged a cumulative record of 129-117. In Rivers' first three seasons with the Celtics before the start of the Big Three Era, the Celtics went 102-144. Granted, Ainge's strategy during those seasons was to acquire young assets, and there might have even been some tanking involved in hopes of acquiring Kevin Durant or Greg Oden with a top draft pick in 2007, but Rivers was not successful in developing young talent in many instances.

Players like Al Jefferson, Gerald Green, Sebastian Telfair and Glen Davis fell short of their potential in Boston and ended up experiencing varying levels of success in other stops. Maturity certainly was an issue for all four, however, Rivers struggled to bring a professional contribution out of all of those players. Rondo certainly could be considered an exception, although he has yet to refine his game to improve the weaknesses that prevent him from becoming one of the game's best point guards. In fact, Rondo's player efficiency rating peaked in 2009-10 and has not approached the high-water mark (19.16) since. Rivers also has enabled Rondo's immature behavior at times, openly questioning whether referees are targeting his point guard rather than confronting the behavior with Rondo.

Rivers has been at his best in molding defensive stoppers like Kendrick Perkins, Tony Allen, Avery Bradley and Leon Powe. However, Rivers can't take sole credit for those players when the coach has had a defensive coordinator on his staff throughout his tenure, most notably Tom Thibodeau during the championship season. A large share of the credit for the Celtics' strong defensive prowess over the last six seasons must also be given to Kevin Garnett. The C's big man has served as a mentor to players like Perkins and Powe, and the lead communicator on the court for guards like Allen and Bradley. Garnett has made a living anchoring top defensive teams. Until this season, the Celtics ranked in the top five in terms of opponents' field goal percentage each year of the Big Three Era.

Which brings us to Rivers' in-game coaching. Rivers often is lauded for his ability to call plays during timeouts that result in points for the Celtics. The Celtics typically rank among the top teams in the NBA in points per possession following timeouts during Rivers' tenure as coach, however Rivers' end-game coaching seems like a greater measure of impact on wins and losses. During Rivers' tenure, the Celtics have gone 63-61 in games decided by three points or less. We've seen countless final possessions result in isolation plays with Pierce dribbling out the clock at the top of the key before time expires without a quality shot.

Rivers also has struggled to get the most out of role players like Jason Terry and Jeff Green. WEEI.com colleague Ben Rohrbach noted in a column last week that during the Mavericks' 2011 title run, only a third of Terry's shots came from 3-point range, and he created more than half of his buckets off the dribble. On the Celtics, he takes half of his shots from beyond the arc, and almost 80 percent of his field goals come from assists. Prior to Rondo's injury, Rivers was using Terry in the same way he used Ray Allen in previous seasons, rather than play to the player's strengths.

In Green's case, he collected 1.5 offensive rebounds per game in his best season (2008-09) in Oklahoma City. That number led, in part, to Green taking 4.5 shots per game at the rim. Rivers' philosophy is to concede rebounds on the offensive glass as a trade-off for having his players get back on defense and cut down on fast-break points. This season, Green is only averaging 0.7 offensive rebounds and 3.0 shots at the rim. The most common criticism of Green is that he's not playing aggressively enough, spending too much time waiting for passes in 3-point territory. However, his aggressive play is being stymied by Rivers' philosophy.

In this respect, Rivers' coaching seems to run contrary to Ainge's team-building. Ainge has seen the NBA evolve into a league dominated by athleticism and speed with teams like Miami and Oklahoma City leading the charge. Ainge has made personnel moves to address the shift (i.e. Perkins for Green). He also has added depth in recent years in hopes of lessening the burden on Garnett and Pierce in their advanced ages. However, Rivers has not made adjustments to his philosophy, continuing to build around the oldest players on his team rather than incorporate the younger players. He has not used his depth to lessen the burden on Garnett or Pierce besides a slight decline in minutes per game. In fact, both players' usage rates are higher this season than they were in 2009-10.

Rivers often excuses poor shooting nights by saying, “It's a shooter's league.” This is particularly true for the Celtics, who rank 23rd among all teams in field goal attempts at the rim and 26th in the league in shots between 3 and 9 feet. The Celtics enjoy the degree of difficulty of the mid-range jumper, ranking second in the league in shots between 10 and 15 feet and fifth in the league in shots between 16 and 23 feet. Despite their inclination to shoot jumpers, the Celtics rank 28th in the league in 3-point attempts and 21st in the league in free throw attempts. When all is said and done, the Celtics rank 20th in the league in points per game, despite having the league-leader in assists on the roster. As of late, a Doc Rivers team is a jump-shooting team that doesn't get to the free throw line or rebound particularly well.

Without question, Rivers milked the Big Three Era for everything it was worth. He pushed every button to get the most out of Pierce, Garnett and Ray Allen as they marched into the twilight of their respective careers. Few other coaches could have gotten their players to buy into Ubuntu as quickly as Rivers managed the feat in 2008. The problem is Rivers is still coaching the Celtics like it's 2008, and the team is ready to usher in a new era.