Yes, the sample size is too small, but the fact of the matter is the team is not rebounding. They have a negative rebounding differential (-0.8 per game) and their rebounding rate is below 50%. So it's not because Love is stealing all the rebounds from everyone else. I expected the guards and wings might see a decline in their defensive rebounding numbers and/or rate on the assumption that Love's outlet passing ability would likely cause some players to leak out early, as we saw with Corey Brewer in Minny.
Varejao, the point of this thread, has been part of the problem. In raw numbers, he is now rebounding below average for a center (only 10.5/48 minutes), after having been an elite rebounder in recent years.
LeBron's average is down from last year, though he is still slightly above average for a SF (he is at 8.1/48).
Love is down (at 12.8/48), though still above average for a PF.
Kyrie, historically a good rebounder for a PG, is down (3.4/48).
Waiters, historically an anemic rebounder, is now among the worst rebounders in the NBA (2.2/48).
Marion is down from last year, but still very solid (8.9/48), plus he has been playing more on the perimeter at SG, which would deflate his numbers.
Even Thompson's rebounding is down (12.5/48), despite playing a lot of minutes at center. More specifically, his defensive rebounding numbers have plummeted.
These numbers are partly due to lack of opportunities -- Cavs are tied for second to last in opponent FG% and so there simply haven't been as many missed shots (at least by the other team), but that's not the only reason.
Anyway, to bring this back to Andy, given the across the board decline in rebounding, his numbers may be less of a cause for concern. There seems to be a deeper reason.