How do Celtics replace Shaq?

What does the retirement of Shaquille O'Neal mean for the Boston Celtics moving forward? Probably more off the court than on it.

Yes, the Celtics performed at an exceptional level when O'Neal was healthy this past season. Not only was Boston 27-9 with O'Neal in the starting lineup but it was 20-5 when he played 20 minutes or more. It's that sort of impact that gave the Celtics the confidence to deal away Kendrick Perkins at the trade deadline, unaware that O'Neal's injuries would limit him to 17½ minutes after Feb. 1 and, ultimately, force him into retirement.

But O'Neal's presence might truly be missed more off the court, where his trademark smile and booming laughter permeated the entire locker room through the early portion of the season, particularly training camp. That prompted even Kevin Garnett to let his guard down at times and savor the moments with both players nearing the twilights of their careers. It was Garnett who flew in from Hawaii just to be at O'Neal's introductory news conference in August, and the two often made reference to how enjoyable the other made the 2010-11 campaign, with Garnett affectionately referring to O'Neal as the "Big Fella" throughout the season.

The Celtics won't get anything in terms of salary cap relief from O'Neal's retirement, this after he signed a veteran minimum deal last summer. Assuming no sweeping changes to the next collective bargaining agreement, the Celtics will again be limited to luring veterans like O'Neal who are willing to accept low-money contracts for a chance at a title, but it's not as if his $1.4 million contract will aid them in pursuing another superstar player (the team is already hamstrung by $56.6 million in contracts to its Big Four).

After the season, Celtics president of basketball operations Danny Ainge noted a desire to get younger and more athletic, two things O'Neal certainly wouldn't have provided if he had returned for one more campaign. Still, the Celtics are now even thinner up front and are likely to have limited resources in enticing big-man talent (midlevel and biannual exceptions, if they live on in the next CBA).

Jermaine O'Neal, who will be 33 at the start of the 2011-12 campaign but entering his 16th NBA season, projects as the team's starting center as the only big man beyond Garnett under contract. Concerns about whether he can hold up to the rigors of an 82-game schedule likely will leave Boston trying to restock the big-man cupboards.

That could include unrestricted-free-agent-to-be Nenad Krstic, acquired along with Jeff Green and a future first-round pick in that Perkins trade with Oklahoma City. Kristic could be lured back if the Celtics are able to use the rights that currently exist for a team to retain its own free agents at modest salary increases.

Top frontcourt reserve Glen Davis is also an unrestricted free agent, and the market is likely to determine whether Boston is willing (and able) to bring him back in that sixth-man role (though it was Davis who ultimately spent the most floor time at center with the Big Four).

The one thing the Celtics will miss on the court is Shaq's ability to force a defender to stay with him. In the Big Three era, the Celtics have sorely lacked the sort of big man who commands constant post attention because of the potential for alley-oop action with point guard Rajon Rondo. It's no coincidence, coach Doc Rivers often pointed out, that Rondo's numbers were otherworldly at the start of the season when Shaq was healthy.

It's also unlikely that any player can have as much of an impact on the community. Shaq quickly endeared himself to the region, setting up shop on a sprawling farm in Sudbury, then engaging in local stunts such as posing as a statue in Harvard Square, conducting a holiday medley with the Boston Pops and dressing in drag as Shaquita on Halloween. O'Neal didn't just make basketball more fun for his teammates, he did it for Celtics Nation as a whole.

Chris Forsberg covers the Celtics for ESPNBoston.com.