The NBA Summer League began today in Las Vegas with the Boston Celtics facing off against the Oklahoma City Thunder. With many players partaking in the tournament who the Celtics expect to participate in the regular season, the Celtics interest in the tournament is relatively high.

Now that Ray Allen is with the Miami Heat, the Celtics will cast a keen eye over their two rookies from last season's draft for different reasons.

E'twuan Moore is a young guard who will need to make an Avery Bradley type of leap before next season if he is to be on the team's active roster. With rumors surrounding Courtney Lee and Jason Terry already aboard, the Celtics are stacked at Moore's position: Shooting Guard.

Moore was a second round pick who the Celtics aren't really expecting anything from. The same cannot be said of the team's first round pick from last season, Jajuan Johnson, however. Johnson is a talented forward, not shooting guard, but how he was acquired will put the pressure on him to perform this year.

The Celtics did not initially select Johnson, they first took Marshon Brooks before trading down two spots with the New Jersey Nets to take Johnson.

Brooks last year proved to be a very promising guard. Even though he is currently embroiled in the Dwight Howard trade rumors, that does not detract from the fact that Brooks has the potential to be one of the best two guards in the NBA. The Nets willingness to let him go is more to do with their infatuation with Dwight Howard opposed to his own future.

Brooks is one of the most sought after expendable pieces that the Nets own. That is because he fills a role in the NBA which is not easy to fill. Brooks shot over 40 percent from the field in his rookie season playing 29 minutes for a poor team. He can at times be a selfish player, but he also has that element of a scorer's ego which every big time offensive player needs.

Considering scoring was such an issue for the Celtics last season, and they've now lost one of their primary scoring threats in Ray Allen, passing up on Brooks could prove to be a major mistake from general manager Danny Ainge.

Ainge obviously couldn't have predicted how this year's draft would go 12 months ago, but now that he has added two forwards to his roster, Johnson must prove to be a special player to justify the team's passing on Brooks.

Had the Celtics entered this year with Rajon Rondo, Avery Bradley and Marshawn Brooks as their guards, they may not have signed Jason Terry or be considered contenders for this season, but the future would appear very bright for their front court going forward.

Brooks is currently available, but it is highly unlikely that the Celtics are able to acquire him. They aren't even trying. Instead, the Celtics are moving forward with Jajuan Johnson, as you would expect any franchise to do.

Hopefully for them, Johnson can erase all lingering thoughts of what Marshon Brooks could have done in Boston.

Cian Fahey writes for the Guardian, Irishcentral, Steelersdepot and FFBLife. You can find him on twitter @Cianaf