This time last summer the Boston Celtics had already acquired Ray Allen and Kevin Garnett and were making headlines once again for signing proven veteran swingman James Posey. A year and one NBA championship later, the team is making headlines for signing the all-but-forgotten Darius Miles. Even though the Celtics will return their entire starting lineup next season, have they done enough this summer to defend the title?

The Celtics took a gamble when they tied up 75% of their payroll in Paul Pierce, Garnett, and Allen. The risk paid off last season but now they are forced to turn to more inexpensive (and inexperienced) options to complete their roster. The bench played a critical part in winning the championship and these newly acquired role players have big shoes to fill.

Who will replace James Posey?
After losing Posey to the allure of a long-term contract, the Celtics were in desperate need of inking another perimeter defender. They began by re-signing defensive specialist Tony Allen in hopes that he can return to his old self after suffering a debilitating knee injury two years ago. The upside is that Allen is familiar with Doc Rivers' system after four seasons with the Cs; the downside is Allen's inconsistency.

While Allen is expected to improve with more playing times, the Celtics have a Plan B in first round draft pick J.R. Giddens. Team personnel gushed over his athleticism and the rookie is determined to bring a team-first mentality to the selfless squad. Giddens is a long defender who can protect the perimeter and could either challenge or back up Allen in the backcourt.

Just as Giddens was a surprise on Draft Night, the recent signing of Miles was even more of a head-turner. Miles has not played in the NBA in over two years (knee injury) and has a history of off-the-court problems. If Miles turns into a success story, Celtics GM Danny Ainge will look like a genius once again. If he is a bust, they don't have much to lose with a non-guaranteed contract. Aside from injuries, the question mark is how Miles, who is facing a 10-game suspension for violation of the league's drug policy, will mesh on such a close-knit team. The Celtics cannot afford to tamper with "Ubuntu."

What can the Celtics expect from Patrick O'Bryant?
O'Bryant was a relative unknown in the Eastern Conference before the Celtics signed him earlier this summer. The big man never cliqued on the Golden State Warriors and in turn spent the majority of his first two seasons on the bench. O'Bryant has been working out extensively with Celtics assistant coach Clifford Ray, who sees potential in the young seven-footer. In order for O'Bryant to succeed, he has to buy into the Celtics system and commit himself to hustling and playing with a sense of urgency. While O'Bryant will not give the Celtics the same experience off the bench as P.J. Brown, he can still eat up minutes for the foul-prone Kendrick Perkins at a low price.

How soon can the rookies contribute?
The answer is, it doesn't really matter at this point in time. For the first time in years the Celtics entered the Draft looking to build toward the future, not find a quick-fix. While Giddens could see minutes this season, he does not have to in order for the Celtics to win. The same goes for second-round pick Bill Walker, who along with Giddens could be a candidate for the NBA Development League. This veteran team is not reliant on the contributions of first-year players and head coach Doc Rivers will not offer minutes until a rookie proves himself worthy. (Even NBA Finals breakout player Leon Powe had to bide his time off the bench late into his second season.) The youth movement is a distant memory and the Celtics are no longer dependant on rookies to fuel their success.

The Bottom Line
Rather than focusing on who the Celtics signed, the better assessment is looking at who the Celtics are bringing back. Despite losing Posey, they have kept their starting five intact. Big men Leon Powe and Glen "Big Baby" Davis will be back with championship-winning experience under their belts and veteran guard Eddie House (and his clutch long-range shooting) is returning as well. The Celtics are not looking for Giddens, Miles, O'Bryant, and Walker to be game changers. The core of the championship team was built last summer and now it is up to these newcomers to uphold the Celtics' winning ways.