WALTHAM — Sometimes, too much of a good thing is not healthy for a basketball team.
Well, take a look at Rondo’s minutes and what the Celtics expect from him and you could make the argument they should be just as concerned.
In the first three games, Rondo has played 44, 41 and 41 minutes, averaging 41.5 minutes per contest, nine minutes over his career average per game. Yes, it’s just a three-game sample so far and yes, that average includes a season of 23.5 minutes in his rookie year in 2006-07 and 29.9 the next, when he led the Celtics to an NBA title running the point. But still, one look at Rondo’s lean body and you see the need to preserve the Rolls Royce of the Celtics engine for all 82 games.
But Rivers took it a step further after practice Monday when he said it’s not the number of minutes but how Rondo is playing on the court that he has to watch closely. Rivers wants to be the one pacing Rondo from the bench, not Rondo himself.
“I’m concerned but not as far as him getting tired but I don’t want him to save himself on the floor,” Rivers said. “There’s a minutes number for him. We don’t know what it is yet. We’ll figure it out where he can play his minutes at full pace instead of knowing he’s going to be on the floor too long and then he starts pacing himself. We need him to be a fast, quick, aggressive player.”
And the number?
“I think it’s 39, 38 but it’s not much lower than 40 but it’s in that area,” Rivers added.
Rivers has said in years past just what a physical drain it is for a guard like Rondo to not only run the offense but play top-end defense that is a staple in the Celtics scheme.
The answers right now off the bench are Jason Terry  and Leandro Barbosa , with the latter coming to Boston in late October as Danny Ainge realized the need for ball-handling depth on the roster. Courtney Lee  can also help lighten the load, switching from his starting role as shooting guard to the point.
But the biggest help of all will come when Avery Bradley  comes back with two healthy shoulders – likely in December – to take a big defensive burden off Rondo.
Until then, Rivers will be watching Rondo very closely.