As a general rule of thumb, it’s not a good thing when an NBA championship contender has a number of unanswered questions with a week to go in the regular season. A baseball or football team can get hot just in time for the playoffs (see: Cardinals, St. Louis and Arizona) but with the exception of the 1995 Houston Rockets, there just aren’t that many flukes — and the Rockets could hardly be considered a fluke when you consider that they had the best player in the world that year in Hakeem Olajuwon.

To be sure, even with their myriad of questions, the Celtics are still one of a handful of legitimate title contenders, but they find themselves far more unsettled then they were a year ago. If we’ve learned anything about this team, however, it’s that they have been able to play through several difficult scenarios. While they aren’t as brutally efficient as last year’s team, they are tested, which you may remember was the major concern last season. That’s the good news.

The bad news is that the injuries have caused Doc Rivers to re-jigger the lineup almost on a weekly basis and cut back on practice time, which has left him with an unsettled rotation and a lot of what-ifs. As the regular season mercifully winds down, here are five questions for the C’s.

1. Really, how healthy is Kevin Garnett?

The Celtics say he would be playing if it were the playoffs. They also say that since his timing wasn’t an issue when he made his aborted comeback that everything will be fine when Garnett returns. They may be right, but until that happens, KG’s right knee is the biggest question mark they face. The Celtics are now talking about a possible return against Philadelphia on April 14, but that’s just the latest date in an ever-changing calendar. 

When Garnett did play, the Celtics were noticeably better defensively (and offensively for that matter) but by the end of his 17-minute run against Orlando, he was not moving well and he has been shut down ever since.

There has been a lot of talk that the Celtics have no chance to repeat if KG isn’t healthy, and by healthy that means 30-36 minutes in all his frenzied Garnett-ness. That’s almost certainly true, but it’s also worth noting that the Celtics should be fine with or without KG in the first round, and it’s at least debatable whether they could take out the Magic without him. So there is time beyond mid-April.

Larry Bird told the Herald over the weekend that Garnett is suffering the effects of playing the game hard during his career. There’s definitely something to that, but Larry Legend, like everyone else, is just guessing about KG’s health.

2. How healthy is everyone else?

Tony Allen made his long-awaited return to the court Friday night and played a handful of relatively uneventful minutes. For as much angst as Allen causes fans, the Celtics need him to fill a backup role behind Paul Pierce that has been largely ignored the last few months. Bill Walker has shown flashes of promise, but the Celtics need Allen to fill out the second unit. 

Leon Powe has still not seen the court, and unlike KG, Powe does not have the track record to suggest that he will be able to seamlessly fit back in the lineup. But Powe was playing at a high level when he got hurt and his back-to-the-basket post-up game would be a welcome offensive jolt to the second unit. Just imagine the possibilities of Powe working down low with shooters like Ray Allen and Eddie House spread out on the perimeter and Stephon Marbury handling the ball.

Perhaps the biggest — and most unfortunate — question mark is Brian Scalabrine, who has had several setbacks related to his concussions and at this point it’s not a given that he will be back at all. It’s been increasingly frustrating for Scal, especially because he was finally carving out a meaningful role with the Celtics. Rivers has admirably shown he won’t take any chances with him and the word that keeps coming up is “scary,” because head injuries remain such an unknown factor.

If the Celts can get two of the three back and ready to play that would be the best-case scenario.   

3. What will the big man rotation be?

One of the effects of the injuries has been a complete lack of big man depth for the last few months. The Celtics have somehow managed to get away with having just three bigs since Garnett returned to the inactive list, especially because fouls will always be a problem for a group that relies on Kendrick Perkins and Mikki Moore. Perkins in particular has made strides in that area and the Celtics need him to stay on the floor and avoid the ticky-tack moving screen fouls that have plagued him in the past.

Part of the reason for Garnett’s smooth transition back to the lineup is that he is rarely on the floor with anyone but the starting five. Behind him and Perkins, however, are three players who haven’t played together that much and are still finding their roles. 

Rivers has gotten a lot of mileage in the past out of riding either Powe or Davis, but not both (Doc likes to have them competing for minutes), and the injuries haven’t allowed him to experiment too much with lineups down the stretch. If everyone is healthy (broken record) then Rivers will have some decisions to make. But remember — PJ Brown wasn’t part of the rotation when the playoffs started last year and Rivers has never been one to be locked into a particular combination if it’s not working.

The important thing is for the Celtics to have options and then hope the coach and players can work out the machinations on the floor.

4. How much rest for Paul Pierce and Ray Allen? 

The other way to ask this question is: How important is it to get the No. 2 seed? The Celtics have the inside track to win the tiebreaker with Orlando if both teams finish with identical records and that might be a more important consideration than the team is allowing. Besides home court, the difference between second and third place is playing either Atlanta, Miami or Philly (third seed) or Chicago or Detroit (second seed) in the first round.

Chicago upgraded by bringing in Brad Miller and John Salmons, but the Bulls are still finding themselves and Detroit is coming apart at the seams. The Hawks, Heat and Sixers meanwhile fall roughly into “dangerous” territory. Already, Pierce and Allen have played more minutes this season than they did last season, and Pierce went through a stretch in late March when he appeared to get worn down.

The schedule is spread out enough to allow both players to recuperate heading into the postseason but it will be interesting to see how hard Rivers rides his veterans next week when they play three games in four days.

5. What, no Rondo questions?

Somewhere it is written that no Celtics playoffs can take place without worrying about Rajon Rondo. The scenarios are this: How will Rondo handle “big” guards, and what happens when the other team simply elects to not guard him and dares him to shoot?

On the first, Rondo has handled the big-guard dilemma far more effectively this season than last. He averaged a triple double against Jason Kidd and outplayed Andre Miller in all three encounters to cite two examples.

As to the other, it’s no secret that Rondo struggled against Cleveland in the playoffs last year, and this year hasn’t gone much better. In three games against the Cavs he has averaged just 8.3 points and shot 38 percent from the field, and if the C’s do get that dream matchup with Cleveland it will be his biggest test.

Still, Rondo has proven this year that he belongs in the top tier of NBA point guards, and the playoffs will be his chance to show the rest of the nation what we’ve been seeing all season. Along those lines, Marbury has teamed with House to give the Celtics an effective backup guard combination. It has taken a little longer than expected for Marbury to get up to speed, but he has been playing noticeably faster in recent games, and the playoffs will be his audition for the rest of the league if he wants to earn another contract next season.

With 77 games already in the books that’s a lot of unknowns and what-ifs for the Celtics to have to sort through at this late date. Because of that (and Cleveland’s home court dominance) the Celtics will not enter the postseason as the favorites, but they have earned the benefit of the doubt, not only with their championship rings but also with their resourceful play this season.

In one way or another all of this comes back to Garnett and his knee. If he is healthy, everything else falls into place.

Paul Flannery covers the Celtics for WEEI.com.