In addition to his five starters, he’ll use Ray Allen , Mickael Pietrus  and Greg Stiemsma  off the bench. Sasha Pavlovic  or Keyon Dooling  can absorb a few minutes here or there and Ryan Hollins  is the emergency big man in case of foul trouble.
That’s a mighty thin rotation, but its really all Rivers has to work with as the playoffs approach. Jermaine O’Neal is out for the season. Marquis Daniels  simply hasn’t been able to regain his form following spinal surgery and the Purdue rookies have been relegated to the deep ends of the bench.
In theory, that eight-man rotation offers versatility and intriguing matchup possibilities. Rivers got a sneak peak at using Allen off the bench before his ankle injury flared up. Having Allen and Kevin Garnett  on the floor to start the second quarter was a huge upgrade over some of the lineups he’s been forced to use this season.
The real key is Pietrus, who has the ability to guard multiple positions and he was sorely missed in their 118-110 loss to the Knicks on Tuesday. New York started three guards and forced the Celtics to use Brandon Bass  on Carmelo Anthony at times.
Bass has proven to be a willing defender all season, often matching up with much larger players, but Anthony is a tough cover for anyone, let alone a banger like Bass. With shooters like J.R. Smith and Steve Novak bombing away from the perimeter, the makeshift second unit without Pietrus and Allen was powerless to stop the onslaught.
The Celtics won’t play the Knicks in the playoffs barring a rash of upsets, but whoever they face, the one thing that is perfectly clear is Rivers needs all eight of his top players if his team is going to make a run. There simply isn’t enough depth to withstand any more injuries.
This sets up a problem for the coach.
The Celtics have four games left and after Tuesday’s loss they have fallen a game behind both Atlanta and Orlando in the loss column in the race for homecourt advantage in the first round. The Magic visit the Garden on Wednesday and the Celtics play the Hawks on Friday in Atlanta. The C’s would have the tiebreaker based on winning the Atlantic Division, but if the Hawks or Magic have a better record, they would get the advantage in the first round.
Home court is nice, but ultimately, that’s far less important than health and the Celtics are walking a thin line right now. Allen missed his fifth straight game with a bad ankle — the 11th game he’s missed in the last sixteen — and Pietrus sat out with a bad knee, leaving the bare-bones bench to be outscored by their Knicks counterparts by a whopping 53 points.
Additionally, Rajon Rondo  landed on his tailbone after taking a hard fall and Paul Pierce  took a knee to the thigh. Rondo has been wrapped up like a mummy for the last few months when he’s not on the court, an unfortunate side effect of his slashing game. Pierce has battled small injuries all season, including various foot and heel ailments.
For a team that has sustained two heart surgeries, Pietrus’ concussion, Allen’s ankle and O’Neal’s degenerative wrist condition, they have actually been somewhat fortunate.
Garnett has missed only one game because of an injury and Pierce had played every game since returning from a preseason heel injury before sitting out their game on Sunday in Charlotte. Rondo missed eight games with a sprained wrist, but has held up despite playing a team-high 37 minutes a night. Bass has also been a steady, reliable presence despite missing time with a knee injury.
They have been a resilient bunch all season, but even they have their limits.