Hopefully for them and their championship hopes, he comes back ready to play.
Shaq could be pivotal to the success of this team in the slowed-down, more grinding style of basketball that is played in the NBA playoffs.
Ever since the Celtics traded away Kendrick Perkins at the deadline in February, they have struggled to win games, going 10-7 since February 26.
The idea was that in picking up Jeff Green, the Celtics would have a young winger who could score in bursts, stretch the opposing defense and learn to be more of a defensive presence when surrounded by such good defenders.
He was slated to be a better version of Tony Allen, who signed with the Grizzlies last summer and is a player that the Celtics are missing, oddly enough.
Allen was known as the player with too much confidence in his abilities, who would take any shot if he thought he could make it. He was also a guy who could defend anything that moved. Allen was a versatile defender on the perimeter who could switch down low and body up guys six inches taller than himself.
With Tony Allen, the Celtics had a scrappy, risk-taking defender who would sometimes show up and do good things on offense, and it helped them immensely.
How far can the Celtics go without Shaq?
Jeff Green is now there to stretch out opposing defenses and be the anchor of the second unit, which he is.
The interesting thing with the Celtics is the fact that they aren't necessarily better or worse statistically—they are scoring just about the same number of points and allowing the same number of points than they were before they traded away Perkins, making their starting center Nenad Krstic.
Krstic had his good games for Boston in the week following his acquisition, but he has fallen off as of late and isn't contributing as much as they need. He is averaging 7.5 points and 4.5 rebounds over the past five games, while shooting only 40 percent.
Against supposed high-scoring teams, such as the Suns, Knicks and Warriors, they are fine because they can defend away from the basket with little problems and can make up for the three-point shot by either pounding it down to Kevin Garnett or shooting the three themselves.
They have troubles, however, when a team has more than one strong guy down low, as Kevin Garnett can easily corral one, but Krstic isn't much help nabbing the other.
The Clippers attack with DeAndre Jordan and Blake Griffin, the Jazz with Paul Millsap and Al Jefferson, the Grizzlies with Zach Randolph and Marc Gasol, the Pacers with Tyler Hansbrough (a monster over the past few weeks) and Roy Hibbert.
Oftentimes, the Celtics can shut down one of the big men, but not both, or Garnett and Krstic will switch off throughout the game, leading to the two bigs on the opposing team each going for 15 to 20 points.
With Shaquillie O'Neal coming back to clog the lane and, well...just be seven feet tall and seven feet wide, this problem will go away, so long as Shaq isn't laboring too much.
When Shaq was playing early in the season, he wasn't exactly the model of perfection at center, as he was actually producing similar numbers to Krstic (nine points, five rebounds), but he was doing it in fewer shots and absolutely removing the paint from play while he was in the game.
Shaq would have been the perfect complement to Perkins had they played more at the same time. Shaq could handle the starting center and put up two fouls in the first eight minutes of the game while drawing two on his opponent.
Both would come out and Perkins would go in to body up the backup on the other team and score.
Perkins may be gone, but the Celtics also might not need him. If Shaq was to come back and play 20 quality minutes a game, the Celtics would have a much better shot at getting back to the Finals.
There would be no need for Shaq to worry about scoring, as there are already five players on the team whocan do that. Shaq would just have to focus on making the lane his territory, and biting the head off anyone who came in.
With Shaq on the court, Boston would have someone to keep Dwight Howard on a leash, someone to keep Joakim Noah under control and curb the constant cutting and slashing of the Bulls wingers, someone to absolutely bite the heads off Joel Anthony and Zydrunas Ilgauskas and maybe, just maybe, stand up to the three-headed monster in Los Angeles.
And I'm almost certain that Nenad Krstic could not be that someone.