When Rajon Rondo suffered a season-ending knee injury earlier this season, veteran Leandro Barbosa followed in his footsteps by seamlessly stepping into his role as offensive protagonist at the point guard position. Unfortunately for the Celtics, Barbosa has taken his Rondo act one step too far, as he also tore his ACL and is now ruled out for the season.

Barbosa's injury has come at the worst time for the Celtics. Since Rondo tore his ACL against the Atlanta Hawks, the Celtics had been enjoying a seven game winning streak that included victories over the Miami Heat, Los Angeles Clippers, Denver Nuggets and Los Angeles Lakers. Although he wasn't starting, Barbosa played a key role during that stretch of success. Against the Heat, he logged 30 minutes, scored nine points and had four assists to only one turnover. In 75 combined minutes against the Magic, Clippers and Raptors, Barbosa tallied 40 points, nine assists and only four turnovers while running the offense as part of a committee.

Even though he wasn't as big a part of the team as Rondo was when he went down, Barbosa's loss could cost the Celtics in a similar fashion. The Celtics were able to win without Rondo because they had four guards contributing at a high-level, while Paul Pierce took over some of the ball-handling responsibilities from the small forward position. Barbosa allowed the Celtics to be flexible in attack, while keeping teammates' legs fresh and offering them a ball-carrier on the perimeter who could effectively attack the rim past defenders.

The Celtics don't have a replacement for Barbosa on the roster already, while it would be asking a lot of the team's three remaining healthy guards to continue the level of production the team has become accustomed to. Playing Paul Pierce on the perimeter more would be an option, except that the injuries to Rondo, Barbosa and Jared Sullinger are already forcing Doc Rivers to play with a short hand as is. With Kevin Garnett already logging more minutes than is ideal, the Celtics also need to consistently rotate their forwards. Replacing Barbosa's contribution the way they have Rondo's is not possible because of the cost that would hit the team's continuity.

No matter what the Celtics do moving forward, they must add another guard to the roster. Had this injury happened prior to Rondo's or even just after it, the team could have made a stronger push for Jose Calderon, who moved from the Toronto Raptors to the Philadelphia 76ers in a three-team trade. Calderon would have been the perfect piece to fit into the Barbosa role. In fact, his quality is such that he could have made a decent attempt to replace Rondo's production on his own. Without Calderon on the market, the Celtics would be pushing for value in pursuit of any other potential trade partner. Finding a player with Barbosa's skill-set isn't simple.

Former Celtics' guard Delonte West is the most likely addition. West was most recently linked with a return to the NBA through the D-League, but when Dallas Mavericks owner Mark Cuban announced he had no plans of moving him onto his team's active roster, he declined the opportunity. Instead, West remains a free agent who could be acquired for little compensation. Now there is no doubt that West isn't on the same level as Barbosa, and nowhere near Rondo, but he has proven in the past that he is capable of contributing at this level. He does not possess the same aggressive nature as Barbosa. Instead he offers the Celtics a more rounded guard who can contribute on both ends of the court. He would offer the team greater depth than they have now if not the same on-field production that they have lost.

West is only 29 years of age and spent four seasons with the Celtics already in two spells. The most recent came during the 2010-11 season, when he played in 24 games and averaged 18.9 minutes per game. Statistically West isn't overly impressive, but his experience running Doc Rivers' offense will be what attracts Danny Ainge to his signature.